My commiserations for you. You're in a situation that sucks. your husband is nuts half, if not most , of the time.
I would only suggest to you, that when you talk with him and the counsellor, that you try to keep an open mind.
there's a lot of other things I could say... but I will only say that I think you're doing good by making it crystal clear to him, that his continuing to mess around with OW, eliminates the possibility of a good relationship with you.