My A would hit a spot where I coined the phrase "his drunk would turn".
It is black out, where he would vacate his body, and his eyes, facial expressions, voice quality would all shift into a very ugly place. He has attacked me in this state, said the meanest things ever...
He just got out of rehab, and for the first time EVER was able to acknowledge that he knew about this shift. He knows it, and now he cant go back. He is struggling.
In my research of alcoholism, I learned that when a blackout happens, it happens because of actual short term damage to the memory cortex of the brain. Oxygen is cut off, and the short term affect is a form of brain damage, but the long term affect can be a cumulative condition called alcoholic dementia.
with alcoholic dementia, the person can begin to have personality changes even when not drinking. The damage is long term, even if the blackouts/drinking stop.
Mine drank for 12 years heavily everyday. He went to rehab because I took him to child support court after he stole back the rent money in a blackout. His moods had become unmanageable even when sober, and his mother finally saw it and confronted him about his behaviour.
Learning this kind of thing really takes the humor out of that whole college joke "ha ha he's so drunk he doesnt know what hes doing" thing. Its not funny when you live with it, and it is even scary for a drunk who lives it and cant stop it.
Alcoholism is a progressive disease in more than a few ways. I would try to keep this in mind, because I am now on a long road of recovery for a disease that I do not have, but that affects me everyday because I have a child with and love someone who does have it.
My advice to you is to really take this experience to heart and decide how you want to live. He has the bad alcohol gene, no doubt about that. You do not want to get deeper into a relationship that could have tragic outcome due to a night of liquor consumption.: a car wreck, an attack...or lesser, but still damaging events like emotional abuse at the hands of someone who will not remember it and will probably deny it.
This is serious. Do not discount how scared you felt/feel about what you saw that night.
Make a boundary. Make it clear. If he drinks the liquor, you cannot be with him.
Make sure you state it as your action, not control over his. Very simple:
"I do not want this dark stuff in my life. You can do what you want, but, I will not be around if you do this, because it is not what I want around me. "