My boyfriend was married and had a side chick so I left but....

So ladies long story short... I’ve been dating this guy for almost 2 years. A couple months into the relationship I found out that he was still communicating with an ex. He said he had broken it off but that she wouldnt leave him alone... needless to say she and I had words and she almost got me arrested. Fast forward, a couple more months I found out he was married. He said they were separated and that she wouldn’t give him a divorce which I believed bc he spent all of us free time with his kids and I. Fast forward again, the ex is now stalking me and I just recently found out they are back communicating even after I advised him to get his number changed. Well I left, been ignoring him but he won’t leave me alone. He wants to explain himself but there’s nothing to really explain. What should I do?