you don't. because even though he might have indirectly hurt you, you still harbor feelings for him. it's hard to deal with, i would know, but that's how the human heart works.
my ex is one of my friends, so i have to worry about seeing him every single day at school knowing what went down between us. after a while, the feeling of likingness just kind of faded. i guess it was because i kind of fell for someone else.
i'd recommend either just being friends with him, or confront him. don't make him get back with you or anything, he doesn't want that. obviously, because he ended it. (sorry if i'm being crass.) ask him why, and then point out that he was too busy for you, but allegedly hung out with a bunch of other girls when he wasn't with you. demand answers. it might help you move past the crush. the other thing is to just be friends. get over it, move past it, move on. you know?
i use my hair to express myself