The following lists the Couples and Relations in Bully.
Kissing any character moves Jimmy's faction standing with that character to 100% permanently, regardless of his standing with the rest of the clique.
None of Jimmy's potential romantic partners will be exclusively romantic with him, regardless of whether he attempts to be exclusive or not. Even Eunice, who can't usually get guys interested in her, can sometimes be seen holding hands with Ray.
With Eunice Pound
Jimmy wins Eunice's heart very early in the school year when he retrieves a stolen box of chocolates for her. From then on, Eunice considers Jimmy her "main squeeze." Jimmy is somewhat grossed out by her overenthusiastic kissing style, although he's not above using her affection to his advantage. Eunice is the only girl who will kiss Jimmy regardless of the clothes he is wearing.
With Beatrice Trudeau
Beatrice ends up falling for Jimmy after he retrieves her stolen chemistry notes from Mandy. Beatrice then gets Jimmy to retrieve her diary when it was confiscated by Mr. Hattrick. He doesn't seem to be interested in a relationship with her, although he does return her affections at times.
With Pinky Gauthier
Jimmy ends up on Pinky's good side after he clears a line in front of the movie theater for her in Movie Tickets. They go on a date to the carnival, but after that are not referred to as a couple. Pinky can always be heard cheering Jimmy on during his boxing matches, however, and Jimmy can still kiss her afterward.
With Lola Lombardi
After Jimmy beat Johnny Vincent in a bike race and Johnny went to tune his bike up, Lola left him for Jimmy. However, Lola arguably never had feelings for any of the boys she dated, and eventually Jimmy wised up. At the end of Chapter 3 he told Johnny that he could keep her. This would make Lola the only girl that Jimmy dumped. However, Jimmy can still kiss her after Chapter 3, if he wishes to do so.
With Mandy Wiles
Jimmy earned Mandy's affections during Chapter 4 after he cleaned up the dirty posters that Earnest had made in the mission Discretion Assured. This relationship lasted until the events of Chapter 5 when Gary turned the school against Jimmy. Lines of dialogue from Mandy indicate that she dumped him because of some things Gary said about him to her.
With Zoe Taylor
Jimmy and Zoe get together while he's expelled from school. The final cutscene of the game ends with Jimmy and Zoe kissing on the steps of the school. Presumably, they remain together during Chapter 6, though Zoe (like the other girls) is frequently seen kissing other boys, however this is due to game mechanics.
With other female characters
Upon passing his first Art class, Jimmy can kiss any of the non-clique female students if he presents the appropriate gift (candy for Eunice, flowers for Christy and Angie), and can kiss them at will upon completing Art. Jimmy kisses Angie as part of a tutorial on kissing after passing Art 1, but it is possible for him to go through the entire game without earning Christy's affections.
Jimmy cannot kiss any of the younger girls, although Melody Adams has an obvious crush on him, and Gloria was originally intended to be an older girl. For a short period after running an errand for Mrs. Lisburn, Jimmy can kiss her, but otherwise he can't kiss any adult women. When he interacts with Delilah and Jezebel and Courtney the mermaid at the the Carnival, the in-game icon indicates that he can kiss them, but since they're behind glass he can't reach her. However, if one uses memory patching in the Wii version (via Ocarina codes) in the game, it is possible to place Jimmy within their vicinity, but no matter how close Jimmy is to them, he still won't be able to kiss them. If they are placed in free roam, on the other hand, they are kissable.
With other male characters
On passing his first Art class, Jimmy can kiss one boy from each clique. He must be on friendly terms (60 faction or higher) with the clique and have flowers in his inventory to give to them. The six kissable boys are Trent Northwick, Gord Vendome, Cornelius Johnson, Vance Medici, Kirby Olsen and Duncan. Jimmy gets the same health bonus for kissing boys that he would have for kissing girls, but even after having passed Art 5, he will still have to present the boys with a gift.
If Zack Owens is added to free roam via hex editing, he can be kissed in some versions. He uses the same leaning and sloppy animation that Eunice Pound does because their skeleton is rigged to "Fat".
Probably the most well known couple around Bullworth. Johnny calls himself the "King around here", and Lola his queen. Their relationship has spread a severe amount of gossip around Bullworth and plagued by Lola's infidelity. Johnny is endlessly willing to take her back it seems, and Lola's behavior when he goes missing indicates a level of co-dependence on her part. Although, after Johnny found out about her cheating with evidence, he broke up with her. Many of the Greasers believe Johnny would be better off without her and even Mandy has sympathy for the clique leader.
Lola is not faithful to Johnny, and engages in an extended affair with Gord. She likes him primarily because, being that he is a Prep, he has a lot of money to spend on her. For his part, Gord finds the idea of dating a girl from a lower social class to be thrilling. After Jimmy gets proof of the affair to Johnny, he and the Greasers set a trap for Gord and beat him up; this apparently puts an end to the affair.
Being the captain of the football team and the head cheerleader respectively means that these two are the poster children of couples around Bullworth. However, after the events of Paparazzi it is thought that Ted dumped Mandy. Mandy then fell for Jimmy afterwards. It is then speculated that she ended up as Jimmy's girlfriend at the start of Chapter 5. Mandy was seen kissing Jimmy in front of Ted and he made no objections.
Seeking to keep up the family tradition of nepotism and inbreeding, Pinky, as Derby's cousin, was betrothed to him. Both often repeat that "cousins are legal". But after Derby was over three minutes late to a date, Pinky left him for Jimmy. Although dating Pinky hurt Jimmy's standing with the Preppies, Derby seemed to be ambivalent to this personally.
Trent and Kirby, both of whom are bisexual, were seen waiting in line together to see a movie during the Chapter 2 mission Movie Tickets. When they were spotted by Jimmy, both of them ran away. They are not seen together at any other time, and no other male students are seen together in this manner.
Ms. Philips mentions to Jimmy that she is "in love" in Chapter 4, but does not say with who. Jimmy initially believes that her feelings are for him, but soon finds out that the actual object of her affections is Mr. Galloway (known to Ms. Philips as Gally-bear). Despite his disappointment, Jimmy aids them in their romance by rescuing Mr. Galloway from the Happy Volts Asylum. They are seen together, cheering for Jimmy, at the end of Chapter 5.
Pinky & Derby
As mentioned above, Pinky and Derby are cousins.
Dan & Thad
They have different last names, but the names were only given on the soundboard. The soundboard has other errors in regards to names. Another purely speculative explanation would be that their parents divorced and that one brother stayed with the mother and adopted her surname after the divorce.
Wade and Christy are probably related, as suggested by their shared surname and bright red hair; despite this Christy and Wade can occasionally be seen kissing due to game mechanics.
Mr. Martin shares the surname, and seems to match up with things that Wade says about his dad in his dialogue.
Bo, Lance, & Gloria Jackson
All three share a lot in common. They share the same surname, skin colour, and intelligence (although being a Jock, Bo tries to keep his hidden). Lance and Bo both have very similar facial features.
Norton Williams and Officer Williams share a skin color and love of fighting, and it is quite possible that Officer Williams is Norton's father.