Round 2, I have been extremely hesitant to post to you because my take on your situation is a bit different than most.
From what you posted in your very first posting, there were red flags that went up for me. You see, I think your h has never fully navigated any of his life's transitions, starting from the age of puberty till now.
He grew up in a very difficult environment where alcohol was the numbing factor for both of his parents. I suspect his parents were not very loving and especially his mother. Your h has a commitment phobia and this phobia is one whereby he is constantly searching for a "mother's love". He is in love w/the "love" element and the euphoria that he receives from each new partner that he meets sends him on a high that he feels will be there forever. Once he has married the woman and the humdrum of the normal life begins and children come along, the wife's focus begins to turn to the children. Your h then begins to feel abandoned and feels like he is in competition w/the children. Thus, the leaving of the spouse and family once again. As for the second marriage, again, seeking the love of a "mother figure" and when the euphoria wore off and the day-to-day humdrum began again, he was out searching once again. Whenever the spouse's full attention is diverted from him, that is when he begins to disengage int he relationship and start his search once again. The pattern continues to repeat itself and I find it quite interesting that with each new relationship, he stays a bit longer. It could be that he's growing up just a little bit w/each one. I can't help but wonder what his "script" was to the first two wives. I suspect he told them basically the same things that he has told you. He cannot admit to himself that he has a problem that needs to be dealt with. He cannot look in the mirror and say "I have been married three times, what am I looking for?"
At mid life, all of this has come crashing down around him. He is now searching for the answers to his unrest and why he is doing or done the things he's done. I'm not at all surprised that he's in a relationship w/his mother. For that is where his journey needed to begin...he never had his mother's love, i.e., his mother may not have been a loving mother to him as a child. He had to go back to that time and yes, he had to forge a relationship w/her now in order to move forward.
As for the self-medications in his life....he watched what transpired in his life as a young boy and saw how his own parents dealt w/life and the pain and suffering that went along w/it. History has a way of repeating itself. I do hope that he can remain clean and can find his way back to you. It's going to be a long journey for the both of you. He's got a lot of ground to cover in order to understand why he's doing and done the things he's done in his life. I hope and pray that he will come to realize that you are the lighthouse in his storm and will want to return to you when his journey has been completed.
I would suggest that you pick up a copy of the book called Silent Sons. I think it would help you to better understand the journey that your h has made thus far in his life.
The most important thing right now is that you take care of yourself and your children. Your h cannot help you right now for he has absolutely nothing to give of himself. His focus is on himself and what he can do to make himself feel better.
If he is not strong enough to break the cycle during his mid life transition, he may never understand himself or why he continues moving from one relationship to another and that only his mother can provide the motherly love and nourishment he is seeking,i.e., the love of a spouse is so different from a mother's love. During this time, he will need to accept all that has transpired and forgive those who have stunted his emotional growth so long ago.
Round 2, I really do hope that I am wrong in my assessment. I hope and pray that he will return to you a better man once his journey is completed.
Sit quietly, the answers will reveal themselves when you least expect them to. The past is gone, the present is a gift and you need to focus on today, allow the future to reveal itself when it is ready.
