My fiance and I are getting married next year and we are discussing the guest list. We want to invite his cousin but do not want to invite her boyfriend.
A few years ago, when the cousin and her boyfriend started dating, the boyfriend did something we consider unforgivable. Supposedly, the cousin (I will call her Jane) was receiving messages from someone attempting to "hook up" with her and the sender was saying some reprehensible things. Her boyfriend (I'll call him John) for some reason thought it was my fiance's brother. I'm sure you can see why that would be really weird. John began messaging my future brother-in law saying John was going to beat him up, "kick his teeth in", that sort of thing. John basically acted crazy with absolutely no proof and without thinking why would my brother-in law message his cousin for sex. It was this whole thing that caused a lot of drama in the family. John ended it all without an apology and defended himself by saying he's very protective of Jane. We haven't seen John since and have only seen Jane a couple times at family functions. As far as I know, John wasn't invited to these functions.
My fiance's mother thinks it is rude to not invite John and is trying to convince us to invite him. What do you think? Should we invite him even though he makes us uncomfortable? I know it's usually rude not to invite an SO but I feel like this is a special circumstance.