I'm so sorry your ex is what he is, but don't hold your breath waiting for him to change. As hard as it is, it sounds like you need help letting go. If you can find someone to talk to do it. You are priceless, and need to be treated that way. It starts with you being good to yourself. If you don't feel comfortable going out with me, then by all means don't. But don't isolate yourself, talk to family and friends and be as social as you feel comfortable doing.
Disclaimer: I am still waiting for an apology from my ex, almost seven years coming. He had a baby with another woman (while we were married and I was seven months pregnant) and never even came close to being sorry. Granted, I was the dumb@ss who went back to him, but still.