Boyfriend problem

Every time me and my boyfriend go out with my friends he gets plastered. Drunk to the point where im having to help him throw up and almost literally carry him into the house. But whenever he decides he doesn’t want to go out with my friends I’m suddenly not allowed to go either. Whenever we go out with his he barely even gets tipsy. It’s like I can’t have a good time because I’m stuck babysitting him or deciding not to drink because he isn’t. I don’t know what to do in this situation I’ve told him it made me upset because the other night he decided he didn’t want to go out with my friends and we stayed home and watched movies which is fine by me I’m not complaining. But the next night I wanted to have a good time because I missed the night before, but I had to spend the whole night babysitting him because he threw up all over my friends house. I don’t know how else to tell him that it makes me upset when he does this.