Maybe you can move your post over to the F&F and will get more responses from a new post then from this old one.
And then when I asked him: "what if at some point I am so unhappy with your drinking that I decide that I cannot stand it anymore and I leave?", he replied: "well.... then I hope that it will be at the point when you are so important to me that when I do my calculations, it won't be worthy anymore to drink".
He answered you honestly – at this point in his life you are NOT important enough to him to quit drinking, (no one will be)……….believe him. And with 20 plus years of drinking under his belt vs the 3 months you have invested your time, energy and hopes on dating…….best bet is…………his past behavior of drinking is a dam good indicator of his future behavior of drinking.
You deserve so much more out of a partner then he would ever be able to give you. Dating is the way we find out if two people fit together…………you two do not and if you feel you are too attached to him already then it’s really not his drinking issue here but your codependent issues.