DPs family ave this thing that if there is ever a birthday/christening/funeral/opening of crisp packet the WHOLE extended family go (and it's never a good night unless it ends up with a fight). Anyway - DP's cousin's DD is having an engagement party in a few weeks. We don't really know her - and I don't want to go. We don't have babysitter available - so would have to take DDs (2 and 8) with us - to what will be a heavy drinking adult occassion. DP says we HAVE to go - I say we don't. He says "we don't have an excuse", I don't think we need one and can just RSVP "Thanks for the kind invite, but we won't be able to come - here's a set of towels..." AIBU???