well if you're not going to announce it, you'd better hope that all of your families and your mutual friend can keep quiet. TBH, I don't understand why you got upset in the first place - "announcing" your engagement isn't and shouldn't be such a big deal - and crying for a few hours over the fact that somebody else has got engaged appears to be bordering on the irrational. Why keep your engagement quiet? so that when you announce it you get all the attention? just speak to your friend before the party, tell them the situation and that you'd like to make it a joint celebration for both couples - it will mean far more to everyone else there, who probably won't be in the slightest bit bothered if 10 couples announce their engagement. Enjoy your party! and celebrate your engagement. You mentioned Bridezilla, don't give anyone else a reason to. Congratulations by the way x