I am also curious what the parents’ reaction is (were they there last night)? Premarital counseling seems like a great place to talk about what your boundaries will be with both families. In this situation, I’d go with “We love you and are sorry you feel that way, but these are our plans, and we would be honored to have your support.” Then just go forward planning the wedding you want to have, maybe just don’t be super gushy about it to her (it doesn’t sound like you are anyway). Be gracious – invite her to your wedding, and attend her wedding – high road all the way. You now know that you are dealing with a person who will not be acting rationally in this situation, so there’s no point in trying to reason with her.