I haven't read every word posted here, but I just want to pipe in for those who are in not just a relationship with an A, but an abusive A.
It is plain and simply a dangerous time when a person decides to leave an abuser. You can't just leave because it would be better for the children, without having a safety plan in place.
I left an abusive alcoholic. I cannot say things are definitely better for my children now than they were when we were living with AH. AH has done some pretty heinous things since I got him out of the house. And he is crazier and more manipulative with the children than I have ever seen before.
The difference is there was no hope for improvement if I had remained with AH.
But we have each of us been through h**l since the separation and it isn't over yet.
So if you are reading this thread and you are in an abusive relationship with an A, I applaud the wisdom here but seriously caution anyone to get out safely.