Dr. Bailey - Grey's Anatomy
Dr. Bailey believes in love but doesn't allow it to override her principles. When Tucker attempted the "your marriage or your career" ultimatum on her, she divorced him. On the day of her wedding to Ben, she dropped everything to save Adele's life. Fortunately, Ben admires Bailey's adherence to her code and waited for her "I do."
Zuko - Avatar the Last Airbender
Zuko finally had everything he wanted. His exile from the Fire Nation was at an end; he was at his father's side, and he could finally have a real relationship with Mai. Then his father revealed his plan to annihilate the Earth Kingdom. Zuko defected to Team Avatar -- breaking up with Mai (with a letter) in the process.
Nolan - The Perfectionists
At first blush, Nolan seemed like just another rich boy manipulating everyone around him into doing his bidding and debasing his girlfriend. It was later revealed he was not a completely heartless prick. His feelings for Ava were real, but he needed to say otherwise to further the investigation into Hotchkiss Technologies.
Clarke - The 100
People look to Clarke for the answers because she has the qualities almost all great leaders embody -- the most important being the ability to make the tough choices. One of her most memorable and gutwrenching choices occurred when the Gounders were about to torture Finn for massacring several Grounders. Sadly accepting she couldn't save his life, Clarke told Finn she loved him before mercy killing him.
Jeff Winger - Community
Greendale taught Jeff to put the needs of others before his own. This includes giving up sex in order to do a bottle episode about finding Annie's missing pen. Jeff made a personal sacrifice not only for his friends but for the audience as well because that bottle episode became one of Community's finest episodes.
Mon-El - Supergirl
TV shows don't plot out musical episodes as a way to bring a couple together for just any couple, but the Arrowverse did for Kara and Mon-El. To balance it out though, they became star-crossed lovers as Mon-El couldn't stay on Earth and then wound up marrying someone else. Even after the love triangle sorted itself out, Mon-El realized he couldn't stay with Kara because the future needed him more.