I see what you are saying here. She continues to use his big drunk as her leverage....and he keeps buying into it b/c of his guilt. But then she gets waaaay out there and is totally unreal about reminding her of sad times!
I know how women can keep bringing up things in the past....and she will, as long as she can get away with it.
Let me share something that kind of backfired when I was standing at the crossroads. I was not a willing partner, to say the least, and I was not about to let my H "shame" me about my EA with OM......so I told him that I would not even listen to him or talk to him unless we agreed to not bring up things in the past that had been hashed and rehased. He quickly agreed to that...b/c frankly, he was tried of hearing me b!tch about the same old stuff. Well, I found out that it was a lot harder for me to stick to that agreement than it ever was for him! But here's the thing....I learned that I could move forward without always refering to the past. I stopped throwing up his "failures" and my "disappointments".
I wished I knew how to say this better, but when in this kind of stitch....the LBH needs to have a "point of reference" in the R and tell his WAW that he has apologized for his wrong doing and that he's sorry for the pain she's had as a result of his actions (even if they were good intentions, like supporting her during death of family, etc.), but from THIS POINT ON....he will not repeat his apology and he will not continue to rehash what has happened in the past. The past is just that....past. Nothing can change it and to live in this tortured state will only bring more pain for the future. Then he can ask his WAW if she is willing for them to start at THIS POINT ON in moving forward together. If she is not willing....or if she starts all over again bringing up the past...then that is a sign that things will not get better until she has professional help. (There is a reason the scripture has "stubborness" and "witchcraft" in the same verse.) She needs to get off her high-horse and stop acting so entitled and look in the mirror!!!
It is not about what you feel should work in your M. It is about doing the work that gets the right results. Do what works!