In the franchise, Sheen has a major crush on Libby, who constantly rejects him. In fact, it is hinted even in some of the earlier episodes, though it first becomes a more major plot point after Sheen was exposed to Jimmy's love potion in Love Potion 976/J. Their relationship develops throughout the show. However, Libby does often stick up for Sheen when Cindy or Nick yell at him and comes to his defense. Libby also thinks Sheen is cute and funny. It is also shown that Sheen cares about Libby more than Ultra-Lord and that Libby cares about him more than music.
In Planet Sheen, Sheen gets a new love interest, the alien warrior Aseefa and Libby sadly isn't mentioned or brought up at all. It is unknown if they were still dating at that point. This was panned by many fans of the original series who supported Sheen and Libby's relationship (and for Sheen acting totally out of character). However, The Tomorrow Boys implies that Sheen did return from Zeenu and probably fixed his relationship with Libby, but the future could still change. There's also speculation that Planet Sheen might be non-canon, but nothing is confirmed.
Romantic Moments (in order)
- In the movie, Libby sticks up for Sheen when Nick yells at him.
- In Party at Neutron's, Sheen tries to get Libby to play spin the bottle with him, but she doesn't want to participate in that game. When they do play, it lands on Libby and Sheen puckers his lips to get kissed, but she slaps him.
- In Beach Party Mummy, they are dancing together and Sheen says that he loves Libby's new look.
- In Operation: Rescue Jet Fusion, when Sheen jokes to Jimmy and Carl that he'll marry Beautiful Gorgeous, he says Libby will be jealous.
- In Jimmy for President, Sheen tells Libby that when he becomes class president, she can be his first lady and he flirts with her a few times in the episode, despite her rejection and disgust.
- In Love Potion 976/J, Sheen falls in love with Libby under the effects of Jimmy's love potion and they go out on a date. When Sheen starts rushing things, Libby suggests that they slow down and Sheen agrees. At the end, he used Jimmy's cure, but still likes her after this, almost proving that he has always loved her. This starts Sheen and Libby's relationship arc.
- In The Junkman Cometh, Sheen wishes he could see Libby's smiling face again.
- In Sheen's Brain, Sheen becomes a genius, gains psychic powers and plots to destroy Retroville. He forces Libby to be his queen, but only after bribing her with robes and jewelry. However, Sheen doesn't listen to her when she tells him to stop hurting Jimmy and Carl. When Sheen becomes a god, Libby becomes fed up with his tyranny and leaves him, while Sheen chases after her.
- In The Great Egg Heist, Libby gets annoyed and jealous when Sheen flirts with Peggy.
- In Win Lose and Kaboom!, they have an arc of where they are trying to working out their relationship. Sheen says that he's been reading a book on how to impress her and starts making up nicknames that annoy her. During the second event, Sheen tries to impress Libby by winning the game on his own. At the end, Libby says that she likes Sheen just for who he is.
- In Stranded, Sheen told Libby that if he dies to promise to remember him to which Libby told him it has only been a few hours, but Sheen yelled at her to promise him to which she does.
- In The Tomorrow Boys, when Libby becomes an evil dictator in the the future, Jimmy, Carl, Sheen and Goddard go to Libby's party and destroy the Jimmy's gift (which made her evil in the first place, thanks to Carl). However, they also ruined Libby's birthday party and other gifts and she gets mad at them. Sheen later explains everything and apologizes. Knowing that Sheen risked his life to stop her from becoming something she's not, Libby forgives him and invites him for a date, but only after he, Jimmy, Carl and Goddard clean her house and pay for her gifts after they destroyed them. Then, she blows him a kiss.
- In Crouching Jimmy, Hidden Sheen, when Libby is kidnapped by Yoo-Yee, Sheen goes to Shangri-Llama to fight Yoo-Yee and get Libby back. When Sheen is knocked out, Libby finally admits to being his girlfriend and that gives him the eye of the tiger and he defeats Yoo-Yee. This episode reveals that Sheen cares about Libby more than Ultra Lord and at this point, Libby starts to realize this and learns to appreciate Sheen. This episode also reveals that Libby cares about Sheen more than music.
- In Lady Sings the News, Libby lifts an unconscious Sheen and carries him home and calls him a cutie at one point in the episode.
- In The League of Villains, Libby reminds Cindy that the reason she's helping Jimmy is because she's in love with him, but she is too proud to admit it. Cindy then reminds Libby that she feels the same way about Sheen, which Libby denies. The two then exchange knowing smiles.
- Sheen and Libby are the only two protagonists in the franchise to become evil.