To make a long story short: My fiancé's younger sister (19 years old) and I used to be good friend. As of recent I don't consider her a good or close friend anymore, but I have been maintaining our friendship because she still values it and for my relationship with his family. However, recently his sister has become unbearable. She has a history of acting out when she doesn't get her way, but it's getting worse. This week alone she has TRASHED the house completely, made a scene and throw stuff at people during a family dinner out, gone on a shopping spree with other's money for 'revenge' - all because she didn't get her way. My fiancé and I are both sick of her and have decided it would be best if she weren't in the wedding party anymore incase she has a tantrum and ruins the wedding. However, she always views herself as the victim, so we know she won't understand where we're coming from. Does anybody have any advice on how to tell? Or what to do in this situation?
Thanks!