FI's sister (19 yrs old) is making a royal mess of her life at the moment and can't seem to see how her selfish behavior is putting a strain on the entire family. Where this becomes a wedding issue is that she is a BM and she recently got back together with an ex-bf and is expecting to be able to bring him to our wedding. Invites need to go out in the near future and we need to make a decision on whether she gets a plus one.
FI doesn't want to give her one b/c she continues to prove that she makes ex/current bf a priority over her family. The sh*t hit the fan over Christmas when she had this bf come over to the house during Christmas dinner after her parents had told her no and while FI and I still weren't aware that he was back in the picture (and she knew it would be an issue, as FI didn't like him the last time around). This was the last straw for FI, who doesn't want her parading him around our wedding, disappearing when she has BM duties to be with him, and in general, being absent from his wedding. I agree with him and we both are willing to deal with the drama that will ensue if we do not give her a plus one (and basically tell her the reason is that she is a very important part of our wedding and we want her to be PRESENT at our wedding), but FMIL doesn't think the drama is worth it. WWYD?