My XABF started as a problem drinker, and tried to cut back.
I learned to cross my fingers, but not hold my breath.
Unfortunately in XABF's case, it didn't work, everything escalated, and there was no stopping that freight train.
Ultimately, I decided that it didn't matter whether he was an alcoholic or not.
I had a problem with his drinking, and I had a problem with his wants constantly overriding my needs, and the only way to solve both of those problems was to leave the relationship, because there was no evidence of positive change coming from his end (and I am incapable of changing another human being, and ran out of ways to safely change myself while he was around).
Maybe your ABF can cut back on his own, maybe he can't.
It sounds like you have also already come to that conclusion, which is great!
I just wanted to pop in and let you know what happened in my case.
You have come a long way, emotionally, in such a short time.
Keep looking for answers, and information. It helps
so much, and it's great not to feel lonely, isn't it!