@The O.P, sorry to hear that. Next time just lie. I don't condone lying of course, but sometimes you need to in cases like this. Just tell him, oh, sorry, but I'm not feeling well, or that you just got your period.

If for some reason you do end up stuck seeing these people, then try to get there before they get wasted and then make an excuse to leave early. That's what I'd do. Your husband shouldn't betray your confidence like that. Some people can't keep anything to themselves unfortunately, so in that case, the less you tell them, the better.