Well...
My parents separated when I was too young to remember and I have not heard from my biological dad since. Have no idea where he is or who he is. It bothers the hell out of me and I do hope to find him someday.
As far as your situation is concerned...from the perspective of a child of an Alcoholic...i must say that separations from the alcoholic especially when that person wont change and is not even remotely interested in changing is a positive thing. Seeing Mommie leave Alcoholic Daddy is not a bad thing. You show your strength and you will be an active agent in improving your life. Separation does not have to be permanent. If Dad gets his act together, maybe the family can get back together. If Dad doesn't, then the family will not have to suffer through his disease daily. Separation will give Mommie and the kids time to heal and learn more about the disease together. Keep in mind that distance does not have to be hostile or permanent. It is for your good and the children's good.
That is what I think about it. Distance from my alcoholic mom has made it much easier for me to heal and have a relationship with her.
Good Luck and God Bless,
~Def