How to get my significant other to allow me to make my own choices.?

This is a really tough question because not drinking is usually a good and healthy choice especially if it was causing trouble between you before. BUT I know how you feel. My husband isn't much of a drinker and I used to be a pretty heavy one. He used to try to get me to not drink when he wasn't around when we first started dating and we sat down and discussed it. I found out that he didn't like me drinking without him because he worried about me and he HATED me drinking with one of my friends because we would get really obnoxious. I was able to see his point. I explained to him that I don't like soda/pop and that if I'm going out then I really would rather have a glass of wine or a few drinks. Once he realized that I do not like Coke but I love wine he was a bit more understanding.
It sounds like you and your BF need to do the same. Does he not want to drink because he's got his own issues? Maybe he's struggling with alcoholism and doesn't quite know how to say it? If it's something like that then you've got to be supportive of him because that's a really tough road. If it's just because he doesn't like drinking or doesn't like how the two of you are when you drink then maybe come up with a compromise. Maybe DO go to the clubs in Mexico but don't get wasted and only have a few drinks.