snowfall - You have my heartfelt sympathy. Almost everything you describe is how it was for me and my husband. It was many years ago, but I had to leave him - and for the same exact reasons. I know he regretted deeply losing me and his son - but he never was able to sustain a sober life. I remember him saying to me once, "I thought it was for better or worse... but you're giving up on me." Part of me still feels like I could have done more, but there was never a sign that he was going to change. I could not go down with the ship.
I ended up on the other side of things later on - and had my own battle with alcohol. Now I'm even more confused as to why he couldn't reach out for help so he wouldn't lose his family. When I had to, I got sober and faced reality. I can't imagine that I would have let him go if the situation were reversed.
I'm glad you joined us, and I hope it will help with the anxiety and sadness you are feeling. You're not alone in dealing with this.