Shellcrusher,
I am so sorry for your situation and the disappointment that I know that you are feeling. You are faced with some very difficult choices and if you put your son first it will help you. That is what I am doing. There are parts of me that want to stay with my husband even though he has abuse issues.....I know that it is crazy but I'm just being honest. BUT....I know that I cannot expose my sons to any more chances.
People can and do get sober. It's better for them to do it because THEY want to do it and not because that is what they have to do to stay with us. It is always a half hearted effort if that is the case but it never really works in the long run. There is nothing wrong in removing yourself and your son from the situation and then saying...do what you need to do for the next year, get sober/into recovery, and then we'll talk. That way you are dealing with someone that has really dug down deeply and you won't put yourself and your son through increasingly more painful days.
My husband got sober from cocaine/crack 5 1/2 years ago but didn't dig down. Those behaviors and addict thinking eventually have eroded our relationship. Just not using isn't the secret....addressing the underlying issues is. I have thrown away 5 years of my life trying to make it work with someone that hasn't done his share of the work. I have suffered, my sons have suffered. I hope and I pray that you won't be me and need to take the long way to the same point....... No matter what your choice there is love and support for you though. I know that we all get it when we get it. I'm trying to be gentle with myself because I'm upset that it has taken me so long and I have sacrificed so much.