As much as it sucks, you have to remind yourself that you're better than he is...and that it's his loss. Act like you're the happiest you've ever been and better off without him. Even if things are still a little shaky and the relationship ended on an awkward note, DON'T be awkward. If you see him or talk to him act like everything is in the past. I know it sucks because you keep thinking of all of these things you want to say to him but you know you can't. I do a little strategy where I write everything down, shove it in a hidden place, and leave it there. The feelings are still out and it's a good way to vent, yet you don't look desperate. Sometimes I wish I could take my own advice. But just look forward and don't crawl back to him in all circumstances. He had you once...don't give it up to him in the end.