I don't know if I would bring up the beer thing at all. I would simply say that you've gone over your budget again and you realize that you can't make it happen.
You know, I did this dance with AH for a while too. He would be nice because he needed money (or sex, for that matter), I'd give it to him, then find out he was still talking to the "friend" he had an affair with, I'd stop giving him money, etc. Oh, and guess who finally got a big check and refused to give me any money when I needed it? Now that I've stepped back a bit, I think that I thought my helping him would make a difference in his choices. It's so hard as a codependent to see that dynamic in each and every little situation or interaction between AH and me. I constantly have to ask myself what I hope to gain. It helps that we've now cut the ties financially. If he ever comes crying to me for money, I'll say, "Sorry, it's not in the budget. Good luck and goodbye."