It seems Max has a bit of a soft spot for Stacey. What Bradley said about Max's change of feelings for her, made a lot of sense, and how he's always on her side.
Through the whole abortion thing, he tried his best to comfort her, and defend her. And he said he wanted to be her friend. And he definetely fancies her.
I think they have quite a nice relationship. It's just a fling, but maybe it's not just about sex. Of course it probably is. Maybe i'm just being naive.