Details: Mouth developed a crush on Brooke in season 2 although she thought of him as a brother. But Mouth moved from his crush as Brooke didn't reciprocate his feelings. In the season 4 they went to prom together. In the finale of that season, he finally gathered the courage to kiss her.
Details: Erica was Marvin's first girlfriend and they started to date following Erica losing class president and realizing she had no friends but she and Mouth grew close and started dating. She broke up with him when she started seeing a surfer and became popular leaving Mouth bitter.
Details: Rachel and Mouth had a complex relationship as they were never official a couple but both held eachother in extemley high regard. Rachel initally targetted Mouth and befriended him in order to spite Brooke but a relationship eventually developed. However, while Mouth developed real feelings for Rachel her's were more superficial as she was quick to drop Mouth for Cooper and didn't pay him much attention during her crush on Nathan. Rachel brought out the dangerous side in Mouth, which he liked, and this caused him to leave for New Orleans with her after she expelled from school. The two embarked on a near-romantic relationship on this trip until Mouth saw her flirting with some other guys forcing him to realize there would always be other guys with Rachel. Rachel then left leaving Mouth stranded and alone, ending Mouth's crush on her. The two do, however, remain close friends.
Details: Mouth helped Brooke Davis with her fashion show where he meet Tia and became very nervous around her and she stated that she liked virgins and invited him out with his friends but he instead went out with Gigi.
Details: Mouth and Gigi were sports announcers at Tree Hill High together and they started to date despite reluctance from Mouth but they broke up after a short time due to Mouth leaving for college and Gigi didn't want a long-distance relationship. But nearly five years later Gigi became Mouth's intern and they flirted a lot despite Mouth being in a relationship and she even sent him a semi-naked picture but Mouth ended the flirtation.
Details: The two started to date but struggled due to Shelley's commitments to clean teens believing that she couldn't even kiss Mouth. This caused the two to break up, but Mouth tried to recoil the relationship and finally just before prom at a party they slept together and she took Mouth's virginity and even said she could have loved him but they ended their relationship then.
Details: Alice was Mouth's boss and in hopes of furthering his career Alice and Mouth started to have a sexual relationship with Alice still dating and sleeping with others but while on a date with Millie Huxtable she became jealous and ended their relationship when he wouldn't end it with Millie although he didn't loss his job.
Details: Mouth and Kylie were set up on a date through a dating site by Junk and Fergie and together they went to a 70s themed danced at Tree Hill High but despite offering to go home with Mouth he as he still had feelings for Millie.
Details: Following Skills; Lauren's boyfriend and Mouth's room-mate
moving to LA Lauren and Skills stopped talking her friendship with Mouth grew and they kissed and decided to start dating but since they both still had feelings for their previous partners they broke up. Even though Lauren really like Mouth and wanted to move forward, but she was disappointed that he is still in love with Millicent , but she understood.
Details: The two started to date following being introduced by Brooke Davis. And became a good couple and close and finally moved in together. But there relationship has been an on-off relationship. They've broken up due to Millie moving to New York and losing her virginity to Owen Morello, Mouth flirting with Gigi and Millie's drug problem but despite this they have stayed together through many other problems; moving city, unemployment, etc. but they currently co-host a morning show and Millie is expecting their first child