Welcome tiredntn. It sounds like you have been very supportive of AW. Are you taking care of yourself and your kids? It is hard on kids when their parents divorce but IMHO it is harder for them to live in a house where things that are not OK seem to be OK because they are still going on.
I left. It took me a long time to leave because I was not sure if it would be good for the kids. We have been gone a year. Is it hard-some days it is very hard and their hearts hurt. Other days I see joy in them that was never there when stbxah and I lived in the same house. They know the house they live in now is safe. The people who come over to our house are fun to have around and make them laugh (and just be kids) they are not people who scare them-including their dad--who is pretty scary when he drinks and even when he is sober.
I fought leaving for a long time. I started working on myself, setting clear boundaries. That worked for me for awhile but stbxah is also abusive--so when he could not ruffle my feathers anymore he tried a different tactic-start picking on our older son--that will ruffle her feathers. It worked, it ruffled them right out the door.
It is a difficult decision to make and only you will know if it is the right thing to do and if it is, when is the right time to do it.
Things are hard and confusing right now. Be gentle with yourself. Take care of you and your kids. You might want to read Codependent No More by Melody Beattie. It helped me to understand why I am the way I am and I turned my attention from stxah to my own recovery. I am not there by a long shot-but I feel more sane than I have in years.
Come back and post often. There are a lot of great people here who helped me take off my rose colored glasses and see what my life really was and helped me realize what it really could be.