AllyKat,
You can't control his drinking. What you can control is how you handle the situation. If you haven't already, you may start losing friends because of his behavior. What I would do is if he has been drinking that day or you are worried he will drink and then cause a scene, say "I'm going to go to dinner with them by myself". Don't turn it into a fight, just walk away and go to dinner. You may mention "they didn't want you there because of your drinking", not as a way to get him to stop drinking but as a way for you to take off. If he then says "oh you should stay with me then what the hell!", don't give into it, this is how alcoholics alienate us and we lose friends, become weaker and end up spinning on the merry go round. Of course we choose our actions, because we can control what we do.
I once had my XAGF muscle her way into a weekend trip with friends. She had not been in the plans. I should have drawn a boundary and said "nope we all made plans that didn't include you I'm sorry." and gone and had a good time. Because I brought her I wrecked my weekend and my friends weren't at all happy that she was there.
Anvil said it best. Those are minimum requirements that anybody worth your time should have, in addition to all the things you want out of a relationship. From what I have read so far there is a problem, and like many of us, the problem is way bigger and has affected us way more than we would like to admit. Big arse elephant!