I just want to say, he cannot refuse to "give " you a separation.
YOU get an attorney and a plan and you just do it. Of course he's not going to agree, that's okay. He doesn't need to.
An alcoholic does not often become a social drinker - but the problem is defining what is an alcoholic; which if he drinks to drunkenness and it's causing family problems - sounds pretty quacky. Regardless, you have a right to live in an alcohol free zone if that's important to you.
If you want out, he doesn't really have any say and it sounds like you're ready. As a matter of fact, you've stayed a year and some months longer than when you were ready. I say, put on your boots! He's going to throw up roadblocks. Step over them.
The cure for anything is salt water: sweat, tears, or the sea.
~ Isak Dinesen