I think that after Max cheated on her in 'people like you..' they decided to see other people, but as is usually the case that works out better for her then for him. She starts sleeping with a bunch of different guys. And he calls her out on it and says she's easy. She freaks out and reminds him that he cheated on HER. And that they aren't exclusive anymore.
So he yells at her and basically says he doesn't want to see her anymore and storms out. As he's leaving his concious says 'what did I just do' and he geniunly feels empty and horrible for what he has just done. However, to cope with it he blocks out these feelings and goes out to get shit faced.
I think that after Max cheated on her in 'people like you..' they decided to see other people, but as is usually the case that works out better for her then for him. She starts sleeping with a bunch of different guys. And he calls her out on it and says she's easy. She freaks out and reminds him that he cheated on HER. And that they aren't exclusive anymore. So he yells at her and basically says he doesn't want to see her anymore and storms out. As he's leaving his concious says 'what did I just do' and he geniunly feels empty and horrible for what he has just done. However, to cope with it he blocks out these feelings and goes out to get shit faced.