I'm sorry you are in such loneliness and pain. We all do understand how you feel and your sense of being trapped. You have the three children--one of whom has special needs--and you are dependent on your AH's income. So you are in a very tough, hard place.
In AA and rehabs, they tell the newly recovering alcoholic to "follow direction." Those with years of recovery or those who specialize in addiction medicine tell the newcomer to stop trying to think and control his way to a sober life, but to simply surrender to powerlessness over the disease and to "follow direction" from counselors and other recovering alcoholics.
So the best thing for you in your current situation, with no options for change that you can immediately see, is, I think, to also follow direction from those who have long experience with recovery from the effects of alcoholics in their lives.
My advice is to return to Al-Anon. You may think it won't help, didn't help, but believe me, everyone addiction expert I have ever met or read, will tell you that is exactly where you need to go, weekly, with full commitment, and find someone there who will sponsor you and work the steps just like those in AA work their steps to stay sober and sane.
It is isolation with the alcoholic that I believe makes most wives lose their sanity. Get out of that isolation for your survival and for your children. They need a stable, emotionally healthy mother and if you make a firm commitment to get help for yourself--the kind of help those with experience tell you you should get--then you can save your family.
If you can afford counseling, I would add that. But Al-Anon is free and whether or not it feels like a fit, it is where you should be.
Pay a sitter for an hour and go. To save your family.
God bless. Wishing you a better life.