Should I date my boyfriend after being together for over a year and living together now that we live separate?

My boyfriend and I have been together for a yr and a half. It has been a bumpy road for us. He is still legally married but separated for 3 years now. We broke up for about two weeks last year and in that time he decided to sleep w her. Needless to say I've had an issue w trusting him since then. He has put forth great effort to make up for it but I still struggled w him having to talk to her even though it was about their son. Nothing he did was good enough for me so I constantly nagged him. Four weeks ago we mutually agreed we needed to live separately. He says we moved in too fast and I wasn't ready because I was still angry about what he did w his wife. So I don't know if we should start over and really date or if we had our run and I should let it go.