Cheating is very painful for all involved. You have experienced this as well as his wife. I don't suggest that you stay involved with this man and work on what it is in you that thought that being in a situation like the one you describe was nourishing for the person you are.
I think if I were you I would look after yourself and wish him the best. He has some deep routed issues that he is aware of and can work out for himself. You are the one that is in need of focus. You have been part of destroying the faith, trust, and self worth of another woman. I know what that is like. It seeps in slowly and creates destruction of ones own sense of self worth, integrity and self respect....
My advice is to forget him and "what to do" for him and figure out what you are going to do differently next time. What you are talking of in your first post is not Poly. It is cheating. If you think poly would suit you then look at this site and others thoroughly and become familiar with the concepts, foundations and strategies that work for poly people.
I suggest doing a search in the tags for "lessons" "foundations" "cheating" "affairs" and see what has been worked through on this forum. There are some really good posts that have helped me and others to no end. There is a stickie for "cheating" also that is useful also.
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