I searched and searched these forums but this is such a weird question I wasn't surprised that nothing came up. Here it goes:
I have a 22 year old cousin, let's call her Melanie. She lives at home with her parents and 2 younger siblings and recently her boyfriend of a little less than a year moved in with them. His mom was moving out of state or something and he didn't want to go/couldn't afford to find his own place so he has his own room at the home of my aunt and uncle. I have never met him.
My wedding isn't until next fall but as my fiance and I were planning a tentative guest list, the question arose: do we invite this boyfriend? I am not close to my cousin at all and I wasn't planning on inviting any of my cousins with a date unless they were married/engaged/living together but this seems to not fit in any of those categories. Melanie has mentioned on a few occasions that she and her boyfriend want to get married but she has said that about literally the last 3 guys she has dated. I feel like it will be impolite of me to address an invitation to everyone else in the house and not him but I also feel like I shouldn't have to pay $180 for a plate to feed someone I've never met and wouldn't have invited under more conventional circumstances. Also, I have other cousins who are older than Melanie and in long term relationships, so if I invited this roommate/boyfriend, would I be obligated to invite them with guests as well? This is a pretty unorthodox situation, I'd love to hear some input!