TV’s Biggest Heartbreakers

Originally a self-proclaimed “dirty mistress,” Mark (Eric Dane) hurt Derek (Partick Dempsey) by sleeping with his wife, Addison (Kate Walsh). After she left for Los Angeles, Mark made the rounds with Seattle Grace’s nurses — at least until they figured it out and formed a club called Nurses United Against Mark Sloan. He’d have been condemned to celibacy if Lexie (Chyler Leigh) hadn’t gone for him. Sadly, they weren’t on the same page about the future of their relationship, so things ended badly on a couple of occasions. Now the poor girl wants him back, but he’s dating someone else. Sigh...