Hi. A lot of couples break up because one drinks too much. I think one thing is for certain and its that he will regret this all if he loses you.
I've been on both ends of this. Early life I was never a drinker and my girlfriend would come home glossy eyed drunk. I was upset to see her like this and was mad because of it.
On the other hand later in life I was the one drunk who lost a different girlfriend later.
From my experience he needs to cut it out completely to keep this together. You're already reaching out to other people. He'll eventually make you so mad you'll want to leave and probably will. That's no life to lead like that. Life throw enough curve balls to sober couples let alone one drunk off his rocker.
If you two ever get married one day and he keeps drinking be prepared for the super high alcohol cost and later in life the medical bills.