LTD has put it perfectly.
If the behavior and actions cause trouble, abuse, etc, it doesn't matter much whether it is due to alcohol, drugs, sniffing socks or a change in weather.......if it sucks, it sucks.
If someone's behavior, is making my life and relationship with them, unpleasant, miserable, full of trauma or whatever, then it is up to me to say so, and if I have to, get out of the way.
It is up to them to take any necessary action to change their behavior, not me.
Have heard it said "oh, George is awful when he's drinking, gets nasty, nags, and does it all his way. When he's sober he is a ***** cat."
Well, I have seen George both drinking and sober, and yep...he is a bombastic, boring, know-it-all, nagging and fault finding pain in the rear.
Sober, he is all the above but just toned down a bit....not so much a ***** cat, as still a tiger, just with his claws held in.
It isn't George who has radically changed at all, it was his wife's perception that drinking caused him to be very unpleasant.....so she blamed the alcohol. I guess it was better for her than admitting he was just a jerk normally.
I know with my RABF, that the tiger is under control right now, but if something gets up his nostrils, he can show he is annoyed.....if he had a few beers under his belt, and tiger is out of the cage, he isn't just annoyed...you see the claws and hear the roars for miles.
Alcohol doesn't give them the bad temper, aggression, cheating, lying, fighting genes.
Those are already there, part of the persona, just dormant and under control usually, like the tiger in the cage.
Alcohol just unlocks the cage door, takes off the controls and inhibitions, and out tiger comes.
I sometimes wonder if blaming the booze isn't both the A and their SO's, using it as the scapegoat, and blaming everything wrong on it, because it is easier that way.
Just a perception of mine, but have noticed it over 20 years and wondered.
God bless