relations with yuuClick on one of the subsections below to expand/collapse the relationship information for each character with Yuu. All information found below will be solely based on the manga version of Marmalade Boy, and NOT the anime version due to the major differences in characters. There may be a few references inside the sections that will refer to a difference between the manga and anime versions. Remember, spoilers are not labeled so please be careful browsing! Enjoy your read!
From the very beginning, Miki had her eyes on Yuu. When the two families sat down for a nice meal to discuss the love square going on, Miki couldn't help but fall for Yuu's handsome looks. She tried to tell the families that Yuu and her could relate to the feelings of resentment that were caused by the marriage swap, but Yuu told her to sit down and eat her meal. He wasn't upset about the swap, and he didn't want Miki to put words into his mouth. Miki tried to argue it a bit more, but after Yuu kept shooting her down, she finally agreed to the marriage swap. It is announced at this dinner that the six will be moving into one large house together so that everyone could remain close.
Miki wasn't happy having to deal with the craziness of two families living together under one roof due to her mom falling for Yuu's dad, and vice versa for the other parents. Yuu asks Miki to accompany him to the supermarket to pick up a few things. On the way back he tells Miki that they should probably attempt to be friends, especially because they are going to be living together. Miki is surprised by his charm and sweet words, and agrees. Yuu sticks his hand out to shake on it, and when Miki puts her hand in, she feels something. She wonders what Yuu had given her, looking down to see a wet piece of chewed gum. She gets angry and runs home because all Yuu ever does is tease her.
Yuu ends up switching to Miki's school. He hits her on the head with his brief case as he pops up behind her outside of the school. She tells him to keep things on the down low. Miki talks to a boy, and Yuu secretively watches them from the side to see what is up. Yuu soon after finds out that Miki had confessed to this boy (Ginta), and that she was denied. He is shocked that they can remain so close even after that pain.
Yuu ends up announcing to the whole school that the rumors of him and Miki living together are true. Miki freaks out and runs into the room to clear up what he said because he made it seem like they were living together alone, instead of with the families. Later that day in gym class, Miki is watching Yuu look like an all-star playing basketball and she gets slammed in the head with a ball. She passes out. Yuu comes to visit her in the nurses office, and asks if she is awake and feeling alright to the nurse. Miki gets nervous and pretends like she is sleeping when she hears Yuu enter in her area. He leans down, kisses her on the lips, and then walks out. Miki shoots up and puts her hands over her mouth wondering what the heck just happened!
The next day at breakfast, Miki and Yuu both pretend like nothing had happened the day before. Miki tells Yuu that he is like marmalade, and he tells her that she is like mustard then. They end up laughing at each other and fooling around. Later on, the family puts on a play prank fight to see if Miki had finally accepted the new family. They all pretend to fight and call off the new agreement. Miki runs in and tells them to stay together because they are actually happy. They tell her it was a joke, and she locks herself in her room crying. Yuu climbs in through the outside window and talks to her. She lets him in, and he explains that they were too cruel that time and that it wasn't very nice. He explains that they were just worried that she will never be happy or accept the new situation. He asks Miki to forgive them, and she agrees too. Miki realizes in her head that she was really just scared that she would never get to see Yuu again.
Yuu and Miki end up going to an amusement park together because Yuu's mother got free tickets from work. He teases her the entire day, wins her an ugly teddy bear that he thought she wanted, and they had a great time. When they were about to go into a mirrored maze, a girl grabs Yuu and Miki doesn't realize so she enters the maze alone. She gets lost and frustrated, calling out for Yuu to help her. Once Miki finally gets out, she sees Yuu talking to a pretty girl. After she leaves, Miki asks about what they did in their relationship, and he just says "usual things." Miki gets grossed out and says she imagined them kissing and doing stuff like that. Yuu admits that his first kiss ever was with Miki. He tells her he knew she was awake because her body had jerked when he kissed her. She asks him why he did it, and he replies that the devil made him do it. Miki slaps him in the face and tells him he is a jerk because he always makes fun of her. She storms off angry.
As Yuu walks home a few days later, he sees Ginta trying to force Miki to kiss him outside their house. Yuu tells him to get off and that he is embarrassing. Ginta tells Yuu that he makes him sick to look at him, and Yuu tells him he doesn't even consider him. Miki wonders if Yuu was jealous or if Yuu even cared at all that Ginta was there. Miki gives Yuu a ticket to the girls tennis team dinner, but he responds saying he got a lot of tickets from other girls too... Miki gets angry and asks for it back because she doesn't want it to go to waste. Yuu asks for it back over and over again until she finally gets in and tells him she will be angry if her ticket goes to waste.
After the family officially swaps partners, Miki runs off to the park alone to think and talk. Yuu had followed right behind her the whole time and sits with her. Miki opened up about how the marriage makes her a little sad and he sat there and listened to her, comforting her. Yuu told Miki he was sad that he didn't get to enjoy a fancy free meal, so they go out to lunch together instead. Miki begins to realize how sweet Yuu can really be. The next day, the parents leave for their honeymoon. Miki gets nervous about being alone with Yuu for a week in the house. Yuu tells Miki he is hungry, so Miki finally gives in and starts cooking. He gives her 40/100 points for the meal because the rice tasted bad. Miki then suggests that they can eat out all of the time because she is horrible, but Yuu tells her that she looks cute putting her all into making food for the two of them.
The two realize that it is Christmas Eve, so they decide to buy a tree together. Miki teases Yuu about getting really tired from carrying the tree. Yuu tells her that he isn't tired at all, and that he could lift her up with one arm if he wanted to. She tells him its a big joke, and that he is weak. He lifts her up in the middle of the street in front of a ton of people. This makes her get very embarrassed as people smile and blush watching them. They run into Yuu's manager at work who tells Yuu he is sad that he quit his job. Miki asks him why, and Yuu tells her he didn't want her to be lonely or scared at home if he had to work late because no one else would be home. They get home and light candles and put the tree up, staring into each others eyes. Right before they are about to have a moment, the doorbell rings and Arimi and Ginta walk in. Arimi talks to Miki in private and yells at her for playing both Ginta and Yuu at the same time, which really messes with Miki's head.
Rumors go around that a male named Miwa had the hots for Yuu, and that Yuu was turning gay for him as well. Miki challenges Miwa to a race, saying that the winner gets to keep Yuu. Miki runs into a pole and ends up in the nurses office again. Yuu is there and acknowledges that that is where they kissed once before. He jokingly gets on top of her on the bed and tries to kiss her again. Miwa tells Yuu that he enjoys teasing Miki too, but that bothers Yuu. Miwa comments on how he wonders if Yuu feels like its his privilege to tease Miki.
Miki, Yuu, Meiko, and Miwa all go on a double date to the movie theater. However, it is so packed that the couples had to split up. Yuu puts his arm around Miki during the movie. When its over, he grabs her hand and runs out of the theater to allow Miwa to have some time getting to know Meiko. Miki comments on how Yuu has yet to let go of her hand, and he says that he doesn't want to. Yuu tells her that they need to go get something to eat, so they do. He also wins her more stuffed animals as well, even though she thought they were ugly, she grew to think they were very cute.
Miki starts to avoid Yuu when he refuses to open up to her when she asks him questions about checking out architecture books. On the class trip she runs away from him, but ended up losing her group and running into him. Yuu asks her why shes been avoiding him, as he brings her to a beautiful spot. She gets rude to him and wont answer, so he starts to walk away. Miki grabs his arm tight and apologizes to him for being so distant. He tells her he never wants her to distance herself from him again. He promises her that he will open up to her more as well. He opens up and tells her that he isn't the son of who she thinks he is. Miki is shocked to hear that and wants to help.
After Yuu finds out the man he thought was his real father, isn't actually his father, Miki runs after him to the beach. Miki warns that they will get sick if they stay on the beach and that they should go home. Yuu asks her to warm him up. He grabs onto Miki, hugging her tightly and crying against her chest. She holds him back equally as tight and cries with him. Yuu tells Miki about how after he found out he felt like he shouldn't exist anymore and for awhile didn't want to look at his parents at all. Then he realized they were the ones who loved him and raised him and he couldn't not be grateful to have them by his side. Yuu then explains that that is why he has a hard time trusting people and opening up. Miki tries to ensure him that they are all one big happy family and that even though the family may be weird, they all love him. Yuu admits that he thought the marriage swap was strange too, but that he loved Miki. Miki explains the Yuu that she doesn't have feelings for Ginta anymore than a friend and that she loves him too. Yuu tells Miki that its all his fault that her lips are turning blue as her leans in and kisses her on the beach. When they return home he kisses her head from behind and tells her goodnight. They both end up really sick from being outside so long in the cold.
Over winter break, Yuu and Miki take a walk and exchange presents. Miki gives Yuu a really nice pair of gloves, and he gives her a beautiful gold bracelet with three pearls on it. It begins to snow and Miki jumps into his arms. They both tell each other they love each other. Miki asks Yuu to take her the next time he goes on a trip for architecture, and he promises that he will take her. Miki ends up picking up a part time job to pay for her ticket when they go on the trip. She loses her bracelet at work. Yuu goes in to visit her but she isn't there. A boy behind the counter follows Yuu out and tells him that Miki is over him and that she threw out the bracelet. Yuu runs into Miki's room when he arrives home and tells her what had happened. Miki is shocked because she told Yuu she had asked him if he saw her bracelet. Yuu yells at her and tells her not to allow weird boys to have feelings for her as he storms out. She tells him she isn't going on any trips with him because he is a jerk, and he responds with "who is taking you?" Yuu gets on the plane to go on his trip right before Miki was about to apologize to him. Miki goes to get her bracelet back from the boy at her job and yells at him for causing drama for her. Yuu surprisingly calls Miki and tells her he is sorry he got jealous and will be home tomorrow and that he saved Kitakyushu vacation for when Miki goes.
Miki tells Yuu that she wants THE ring for Christmas that she can wear on her ring finger. He smiles and agrees that he will. He tells her to pick out something in his room to take for her birthday present that he didn't give her in March because she got something for him in June. He tells her he is finally just happy with the family he has. Miki walks into Yuu's closet to pick out a shirt, and he tells her its hers. She gets happy and he slowly pushes her into the closet and kisses her. He told her that their parents wouldn't be able to find them in there.
Yuu looks through old boxes to find the tree from last year and stumbles upon pictures of his mother with Jin, Miki's dad from college. He assumes that Jin must be his father, meaning Miki is his half sister. He freaks out and runs to his friends house not knowing what to do. He asks Miki to meet him at the park the next day. She runs up to him in his arms and smiles, but he is very cold back to her. He tells her to break up with him because his feelings had gone cold, but he refuses to explain. Yuu hands her the ring she asked for, but she screams at him saying she refuses to accept it if he doesn't love her anymore. He tells her to throw it away then.
Yuu leaves for Kyoto to study away from home. Miki comes to visit him. He is still wearing the watch she gave him awhile ago, but when she looks to the left she sees he is with a girl. Yuu introduces her and says that it is his new girlfriend. Miki runs away and leaves. The girl is not actually his girlfriend, Yuu denied her feelings because he wasn't over his ex. Miki calls Yuu when she is back home and tells him he can still come home because she will be alright. Yuu comes back for summer break. Miki tells Yuu that she still loves him, but that she will not cause him any trouble. Yuu asks her not to love him, but she tells him he can't tell her how she can and can't feel. She backs away and turns around telling Yuu not to come any closer to her. Yuu turns her around and sees her crying. He hugs her tight and apologizes for being so cold. He tells her he loves her too, but they can't be together. He shows her the picture he had saw. She tells him she wants to go on the trip they had promised for one last memory, and then she could finally give up on him.
They fly on the trip, holding hands on the airplane. They have a great time and act like nothing had changed between them. They went sight seeing, ate ice cream, went out to dinner, took pictures, held hands, etc. The last night of the trip, they sat and watched the fireworks together. They get coffee to prolong the night because they were both dreading coming home. They start to say goodnight, but Miki cries and jumps into Yuu's arms. He grabs her and pulls her into his room, kissing her. He tells her that he doesn't care what anyone else thinks, and that he is willing and wants to marry her. He says that the census doesn't know they are related so it wont matter at all. He asks her to endure the pain and to stay with him forever, and that they don't ever have to have kids. She agrees to be with him. When they get home, they ask the parents for acceptance and tell them they know that they are actually blood related. Yuu's mom tells him that he is mistaken, and his father slaps him in the face because it was horrible of him to think that way, especailly all alone. The parents tell them it is 100% okay for them to be in love with each other and stay together forever, because they are not related by blood.
A few years back, before the start of the series, Yuu is cornered by Arimi. She is very persistent in him taking a shot with her and dating her because she knows that they could be happy together. Yuu laughs at how hard she tries to be with him, so he agrees to stay with her for at least three months to see how things go. The two studied together, talked on the phone, went out, and had a blast for those three months. However, like Yuu had told all girls, he wasn't interested in long term or being with anyone, and he ended it with Arimi.
One day when Yuu was at an amusement park, he gets grabbed suddenly. He hears the girl say, "It's been awhile," as he turns to see it is Arimi. She asks Yuu for his new contact information so that they can catch up. She then goes on to tell him that she has a new boyfriend, but after seeing Yuu she is going to dump him to be with Yuu again, because Yuu is better. She runs off when Miki walks up. Yuu tells Miki that he never kissed her in the three months of dating previously.
Yuu runs into Arimi again at the girls tennis event, so he goes in with her. Yuu and Ginta realize that they both have the same tennis opponent, a boy who dated Arimi. Yuu found him annoying because he always bothered and challenged Yuu while him and Arimi were dating. Arimi gets very jealous of Miki, and tells her all about her and Yuu. She also brings Ginta along to ruin the Christmas Eve Yuu and Miki were going to have alone. Arimi sits by Yuu and tries to make sure that Miki and Yuu can't have any alone time.
Arimi ends up yelling at Miki because she feels like it's unfair that Miki is playing both Ginta and Yuu. Arimi runs into Yuu's arms and tells him that she loves him so much still and that he should stay with her, not Miki, because her feelings are real. Yuu doesn't say anything, but Miki feels horrible.
Finally the day had come when Yuu and Arimi met up for lunch to talk about how he finally picked Miki to settle down with. Arimi told Yuu she wasn't stupid, and that she could see that he had loved Miki for awhile. Yuu tells Arimi that he wants to change and be a better boyfriend. He explains that Miki finally helps him to open up and that he needs to stick by her. Arimi asks if they can hold each other one last time, and he agrees. They hug each other tightly, and Yuu lets her know that she will be her second favorite girl, to Miki. Arimi and Ginta end up dating, so they all stay close friends in the end.
Yuu is approached in the library by the class president, as he sits and smiles brightly at him. Yuu gets freaked out and begins to think that the guy must be gay and is hitting on him. When Miki tells Yuu his last name, Miwa, Yuu freaks out again and it is clear that he just realized something. As time goes on, Yuu and Satoshi become very close. This creates a nasty rumor around school making it seem like the two are gay for each other.
During a family vacation, Satoshi shows up and Yuu runs off with him. Satoshi tells Yuu that he is interested in a girl named Meiko, who happens to be Miki's best friend. Yuu agrees to try and help him get an "in" with Meiko with Miki's help. A few weeks later, Satoshi, Yuu, Miki, and Meiko all go to the movies together. The movie theater was so crowded that they couldn't all sit together so they had to split into two groups. After the movie, Yuu made Miki leave with him to allow Satoshi to have time with the girl that he liked. Although Yuu clearly didn't mind spending alone time with Miki, he was clearly being a good friend by allowing Satoshi to be alone with Meiko for awhile.
Satoshi introduces Yuu to his father, Yoshimitsu, a famous architecture. They all discuss the art forms of architecture and Yoshimitsu gives Yuu some books to study from and a few ideas on where he could go to school to be successful. Shortly after this first encounter, Yuu asks Yoshimitsu if he could possibly be his biological father because Yuu's mother used to work for him. Yoshimitsu says that it would be impossible because his mother and him were never close in that sort of way. Yuu freaks out and runs away from Satoshi, telling him he "didn't want an older brother like [him] anyway!"
After Yuu calms down to hearing that the man he really thought was his true father wasn't his true father, he is still able to be best friends with Satoshi for the rest of the series. Yuu originally became friends with Satoshi simply because he thought that Satoshi could be his half-brother. However, they created a friendship that was worthwhile in the end, which was worth it for both of them.
When Yuu begins to attend his new school, he hears a rumor about how Miki confessed her feelings for a boy named Ginta and was denied by him. To his surprise, he sees them having fun together and always chatting in school. One day when Yuu was on his way home from school, he sees Ginta throwing himself at Miki outside of their house. Yuu steps in and asks them to stop. As Yuu begins to walk inside, Ginta screams at him, telling him that Yuu makes him "sick." Yuu just responds by saying Ginta isn't even worth his consideration.
When a member of the tennis team is injured, Yuu gets thrown on the team partnered with Ginta. Ginta tells Yuu that he isn't pumped to be partnered with Yuu, but he refuses to lose to the opponent so he better work hard and win with him. Ginta approaches Yuu the next day and tells him he needs to come and practice with him, so they do. They end up doing very well together. Ginta and Yuu both realize they hate their opponent in the competition for different reasons, so they definitely cannot lose. Ginta hates him because they have always been opponents and Yuu is annoyed by him because he was always bothering Yuu when he dated Arimi for three months.
Ginta and Arimi make a plan to pretend to be together in order to stop all of Yuu and Miki's fun and to try and get the other two to be jealous. They show up on Christmas Eve to make sure they can't be alone. Arimi yells at Miki for playing both Ginta and Yuu at the same time and says it's not fair and she needs to pick between them. Miki and Yuu end up together, and Ginta accepts it as the truth. Ginta and Arimi end up being together, but Ginta promises to always kick Yuu's butt if he tries to hurt Miki in the end. The two end up being decent friends and learn to respect each other and become friendly. (Their relationship is more friendly in the anime then in the manga series).