Do ultimatums ever work?

My Q refuses to admit he has an issue with alcohol although everyone around him can see he does. No matter which way you approach it, it always ends in denial and instant defensiveness.

We have been together for 3 years and it started off great the drinking was very minimal like a 6 pack max. Now its like drinking as soon as they can. For example, we had a flight at 7am and the airport we were at did not serve alcohol that early. Even though he was told by the bartender they didn't serve that early he made us go through every gift shop or restaurant to look for alcohol.

Any activity we are apart of he can't just go without alcohol. He says he will just have 2 but then that turns into 7 or that he will pace himself but its pretty much constant as soon as he gets his first drink.

A big reason why I am giving an ultimatum is that his personality switches when he has alcohol. He gets verbally angry over little things to the point where it causes a scene. Anything will set him off. If we are in public and strangers intervene or even look over at him, he will look at them and think of the lowest blow insult he can muster up and say it. He says alcohol does not change him but it does everyone that loves him his family, his friends, say the same thing. Most have distanced themselves from him because of this behavior.

I am at the point where I need to give an ultimatum stop drinking or we break up after 3 years of dating. I am heartbroken because I have seen the person he can be but it is getting to the point where I am always on edge in our relationship if he is going to drink and if he does if he will get in a mood.