That is horrible! I know weddings are SO stressful, especially if they are large. Is this totally 100% against her normal character? If so, it might be time to distract her then ask her to step back and see what it's becoming. Marriage isn't about the wedding (though it sure seems like it at the time!), it's about the commitment to her spouse.

Of course that all being said, I remember calling DH at work (before he was DH) and informing him that I think I deserved a &*^% tiara. Fortunately, he agreed. That and he was impressed by the swearing.

I think you need to do what's best for you, too. Maybe you could ask her to tone it down a bit when she's around you?