Well, yeah, he's unhappy--you dumped him! That tends to bum people out. But hey, you had your reasons and you did what you had to do. More power to you. Now do the right thing and leave the poor guy alone so he can get over you.
Yeah, I know--you feel guilty and want to make him feel better, but you can't. All you will do is prolong his agony. You can't dump someone and then hang around him trying to be all happy and fun like nothing happened. You can't cut a guy loose and then try to convince him he is awesome. You just need to disappear and let him get over you. He'll be fine. Give him space.
Thanks for the question.