So my future MIL has recently (last few weeks) started dropping comments to my fiancé that my future sister in law is feeling left out since she's not in the wedding party. Both of his brothers are groomsmen, but only because he has too many close friends to narrow it down to 4 (my number of bridesmaids). However, my sister is one of my bridesmaids, and her husband is a groomsmen... which leaves my fiancé's sister as the only sibling (by blood or marriage) not to be in the wedding party. When asked, my future MIL says that his sister never said she felt left out, MIL just assumes. Was it a major faux pas for us to not have her in the wedding party?