I thought of an ex of mine too right away. And like GBRalph's, mine wasn't a bad guy......we just didn't work together. At that time we dated, he also didn't really know what he wanted and had a hard time trusting girls after being screwed around on a lot, so I had to try and overcome that. It was not easy.
I broke up with him after almost two months, but beat myself up over certain things for MONTHS afterwards. Because I did like him. What helped me? Meeting another guy I was crazy about
Yes, it sounds simplistic, but eventually you ARE going to meet someone who is right for you and you'll have nothing but memories of the first guy.