You've been with him for two years. He's been an alcoholic for 10.
Bottom line, how long do you want to endure this? You get to decide.
The only way boundaries work is if you actually stick by them. Otherwise, they are meaningless words. I have experience with boundaries both as a child of a alcoholics and as an alcoholic.
If he has an enabler, or ally as you put it, willing to spend the amount of time and energy you have spent attempting to save him .... there's really no need for him to do it himself. He knows that. I think you do too. You're obviously a wise person .... I think I am too, but then emotions start taking over and that knowledge and logic goes right out the window.