((HUGS)) Maude. I would not count on your six-year-old not knowing that anything is going on. My DS was 5 when I left STBXAH, and once I was out it became painfully obvious that even though DS thinks the sun shines straight out of STBXAH's rear end, he was and is ALSO very aware of STBXAH's bad behavior. Bottom line: kids know way more than we think they do, and this situation is certainly impacting your child in a very negative way.
I would not create an action plan based on "the situation changing somehow." If it were me, I would begin instituting a plan NOW based on the assumption that things will never be any better than they are at this very moment, and that they will get worse.
Yes, go to Al Anon. See a counselor or therapist, too, if at all possible. The hardest thing is making the initial changes. I literally had to force myself, and fight against every unhealthy co-dependent urge I had to just ignore him. Once I had some practice, though, it became much easier. Ignore, ignore, ignore. If you engage, scream, yell, slap, reason with him, it will NOT help and it will only feed the cycle that robs you of your own happiness and serenity.
As for why you can't just "let" him drink...well, you can't NOT "let" him drink. He will do whatever he wants, and he will find a way to blame you if the outcome isn't what he thinks he wants it to be. He obviously is not even remotely interested in real sobriety, so the time has come for you to put yourself and your child first, and to leave your AH to his own devices. Even if you're not able or ready to separate physically yet, you can definitely do the (admittedly VERY DIFFICULT) work of changing your own behavior patterns and learning how to put yourself first.
