Hi & welcome to SR!
You know... here's a hard truth: Even if you were living together, you wouldn't be able to control how much he drinks, or when, or with whom, or who he drags into his drinking. You would probably try -- I know I did, for the better part of 20 years, when I was married to an alcoholic.
I'm sorry you're dealing with this. It's heartbreaking to see someone you love make decisions that are bad not just for them, but for your relationship. But the thing is, he's an adult. You can't make the choices for him. And please, remember, the choices he makes has nothing to do with you. Alcoholics don't drink because they're stressed out or separated from you. They drink because they're alcoholics.
I'm glad you're here, because there's a lot of good information about alcoholism and what it does to people -- both to the person drinking and to the people who love them.
Hang around and talk and listen. There are lots of people here with big hearts and lots of experience very much like yours.