I've been through something of the same nature, but my dumbbutt went back to him. I ended it for good a while back but I thought that since I got over him the first time, it'd be easier this time. It was harder because I felt like more of an idiot. But I just keep trying to look forward and think of the great things I have ahead of me and if he does pop into my head, I push the thoughts out with thoughts of how miserable he's going to be if he doesn't change his ways and how good of a person I know I am. I have a quote I found a while back that I try to think of whenever I get down about it:

"He's gonna be so sorry he lost you. Forget the past, forget the pain and remember what an incredible woman you are. You do that and he'll realize what he lost."

Chin up, buttercup!