I have been looking for a long time for an answer that will make this decision any easier and have come up with nothing so far... My FSIL and I used to be friends(not close friends, but friends), until I started talking to her brother. That was over ten years ago, but we didn't start dating until 2 years ago. Once we started dating, and I started attending family functions, it was clear to me that we weren't friends. I have tried numerous times to go out with her, to confide in her, and to have her confide in me... Ultimately, I wanted to be friends with her. She has never treated me like a part of the family, or even as a friend. Every time we get together with the family, she demands everyone's attention the whole time and won't let anyone else get a word in edgewise. It becomes all about her no matter why we are all gathering. Her brother asked me to marry him on Christmas Day, in front of his whole family, and she didn't even congratulate us. She went into her room and cried because she doesn't have a boyfriend.... She still has yet to tell us that she is happy for us or to welcome me to the family... And don't get me wrong, I don't need her approval, but here's my issue... My FMIL is now telling me that my FSIL(24years old) has said things like, "she's not going to ask me to be in her wedding, watch. I would bet on it that she won't ask." And with the way that our relationship has been the past two years, why would I? I have asked my FBIL's wife to be my MOH because her and I have become very close, and my FBIL is going to be a groomsmen. So my FMIL tells me that it wouldn't be fair to leave my FSIL out of the wedding party. I don't know what to do because I know how hurt she would be if she was the only sibling left out, and I don't want to leave her out, but WE DON'T GET ALONG. She doesn't even like me, so why would she even want to be included? And the thought of it makes me stress because all I can see is her monopolizing everyone's attention when this day is supposed to be about me and my FH. HELP!!!