Apparently I'm in the minority here, but here's my two cents anyways. I think that would be a recipe for failure. Having your spouse's back is great as long as he/she is right. If you have a great family and you get along with them fantastically (as I do), I would go so far as to say that standing up to your family for the sake of a girl is dead wrong, even if she is right. That would only send all kinds of wrong signals to her. Maybe she'll express her happiness for a short period of time, but eventually she'll lose all respect for you. What are you gonna do if things don't work out for you two? You're gonna lose her and you have already lost your family. I would rather lose the former than the latter.