AITA for not letting my boyfriend's brother stay in the spare room?

Me and my boyfriend have been dating for about a year. We live in a two bedroom apartment. It's a fairly new relationship so he doesn't spend most nights here but he stays over a few nights a week. My brother lives away but he uses the other room when he comes to visit. He also keeps a lot of his belongings in that room. <br><br>Anyway, my boyfriend's brother is moving and he needs a place to stay for a month. He asked if he could stay in the spare room. I don't want a stranger living in the apartment where I keep a lot of my belongings when my boyfriend isn't even there most nights. <br><br>I said he could stay in the living room but my boyfriend is mad that I wouldn't let him stay in the spare room and that it's "not very nice" to make him sleep on the couch.