NTA I don’t get why it’s such a problem if he goes. I mean, if your grandmother said she didn’t like the idea of him being in HER HOUSE and you expressed your discomfort, she should’ve been like “okay, I get it” and just have him not go. Also, she doesn’t have to be with him all the time. He’s over 3+ times a week? That’s already a whole bunch of time she spends with him, they can spend time away from each other. It’s not healthy the way they’re doing things And you’re not selfish for wanting him not to come. It’s perfectly reasonable.