Major player MMC meets his match and falls hard

Looking for a book like this - MMC is a huge player and commitment-phobe, meets and hooks up with FMC and expects her to be like all the other girls and be clingy/fawn all over him after. Instead, she's like "yeah dude that's totally fine! I don't want anything serious either!!" And he's totally caught off guard bc it's never happened before. She proceeds to continue doing her thing, they hook up but she's also hooking up with other people and making it clear she's totally fin with him hooking up with other people too. He gets super jealous and falls hard for her, cue lots of suffering & angst. Eventually he's able to win her over.