Guys: Should I apologize or leave him alone?

I'd just leave him alone unless you do happen to run into him. I wouldn't go try to hunt him down and find him. Just move on from it, i'm sure he has too, but if you ever do happen to cross paths again, and the timing is appropriat, it wouldn't hurt to apologize. Now if you happen to be interested in him now, i'd hunt for him, if not, i'd let it go, you've made your peace with it, life goes on.