It sounds as if he is not willing to make the final cut with his wife. I know you won't want to hear this, but my suggestion is to get on with your life and not wait for him.
I never think it's a good idea to get involved with somebody who would cheat on his wife, anyway. Yes, you did get involved with him while married. But if if does end up working out, then just remember that he is the type of man who would cheat on the woman he promised to stay with "till death do us part."
Of course, it is your choice, and I know I'm being blunt. However, I couldn't deal with this situation. Is your life that much better with him? It sounds like he is taking advantage of you.