"On top of everything else, must go to Smug Married dinner party"

Just Married
Creative Commons Attribution Share AlikeJust Married - Credit: Liza Mae V.
"Smug Married" is another Bridget Jones invention that has entered the lexicon.  It describes people who rejoice in their own sense of achievement at having managed to settle down before their perceived "sell by date"... at the expense of those who haven't.