My finacee sister-in-law (brothers wife) is just shy of crazy. She flips out very easily and has never liked me from the beginning. She doesnt care for me because she feels the family has liked me more than her from the moment i came into the picture. Plainly stated me and her are very different. She is very introverted and im very extroverted. I made my effort to be friendly, paying a cell phone bill and even giving her and old coach purse! We invited her on vacation and even babysat her children. Long story short, she flipped on everyone, including me, and cussed out me, my finacee, and other family members. Then yet again, cussed me out a second time months later. I am not the type to let go of this and I do not forgive and forget easily. People are saying not to worry about it, but i refuse to let her be in attendance at the wedding. She should have no desire to be there anways, but she is crazy and will show up if nothing is said. I dont want to start off on the wrong foot in this new family, but i feel as if she made a decision to act a fool and now must face the consequences. I am afraid i may cause a rift between my fiancee and his brother, although, they are not entirely close anways. (his brother is not a part of the wedding party). How do you think i should handle this?