Hi, welcome and hugs!
One of the first things I learned here was the 3 C's.
I didn't cause it.
I can't control it.
I can't cure it.
He does not need you to quit drinking, he doesn't need your help to control his drinking and in fact his drinking or not drinking has nothing to do with you.
However you are a good excuse for those times he does drink. You didn't support him enough, you didn't love him enough, it was your fault not his. Of course this is nothing but ******** but he will make his problem anyone's but his.
I don't usually give direct advice but I will consider this as sharing wisdom from someone who took up long term residence in hell trying to save an alcoholic,
RUN AWAY! Run away now, don't look back and don't waste anymore of your life on him.
Your investment at this time is small, both financially and emotionally. The longer you wait the harder it will be.
Good luck with your future life.
Your friend,