A friend of mine asked me if she could bring her boyfriend to the wedding, her married boyfriend that is. There has been a lot of fall out within our friends and her family about her dating this guy (or being his mistress). So everyone knows who he is and she has chosen to debut him at my wedding. I stated that I didn't want the drama, but she insists that this is her date, why should anyone care. Can I tell her not to bring this guy or do I have to not invite her? I'm really not comfortable knowingly hosting cheaters at my wedding.