Ah, young love and its accompanying indecisions and insecurities... I don't miss all that at all.
Well, dear, here's my advice:
1. If you dumped him, it won't matter where he likes you or not. You dumped him for a reason, and it's likely that he hasn't improved since then. Let him move along.
2. If he dumped YOU, then realize that he has already HAD a chance to keep you as his girl friend, but for some reason, he thought his life would be better without you. How did you feel then? How will you feel if you get back with him and then he dumps you again? Bad?
Realize that either way, you're running an emotional risk. It might pay off if he has changed and sees your true worth as a person and as someone who makes HIM better just for his being with you. If he hasn't seen you in THAT light, then he's not good for you.