Op. "a bottle of red wine and some beers" - That's a lot of alchohol, and I say definitely an issue. How often does this happen - once a week, once a month, more, less?
If you are planning to stay with him, then IMHO, I' think he needs help. Maybe he had some sort of (to him anyway) issue with his "stamina" before the drinking started, and he believes this is the only way he can prolong his orgasm.
Again, If you are planning to stay with him, I'd suggest that you need to sit down with him, and let him know he doesn't have to drink to give you pleasure. Let him know how worried you are about the amount he is drinking, and that it's probably having an effect on his health, and definitely having an effect on how you view yourself.
Suggest a trip to the doctor - get his health checked out, as there might be something physical wrong. Would he consider councelling?
If you both believe "stamina" is an issue, there are delay sprays, and condoms with numbing agents in them that can help. You could consider "finishing" him manually or orally earlier in the session, and then he should last longer when you do get around to PIV, assuming he recovers fairly quickly. Of course the whole foreplay bit should be mutually beneficial!
Alternatively, you might want to consider moving on.