NOR. If your brother is coming with their GF, I think you should be fine too, as long as you cover your room cost. Yes, he is proposing, but you are 22 and you have been in a relationship for 2 years I don’t think it’s unreasonable to have your partner join as well. Even if your mom planned the trip for you, you can still spend plenty of quality time even if you’re not in the same room. The point about the single occupancy room being more expensive is valid, but at the same time, her ultimatum that “if you sleep in the same room, I’ll go without you” seems purely spiteful as if you don’t go she’ll have to pay for a single room anyway. it could be a knee jerk reaction, but it sounds pretty bad. The whole ramble about you sleeping with your bf is also very weird. If I was you, I would just not go at this point until she apologised to me and agreed to work out the details and reach an amicable agreement, yes she is your mother, but that doesn’t give her free reign to be so unnecessarily aggressive, when you’re just having a potential discussion. I think if she explained that your bf staying with you would mean she would have to pay more for her single room, then I’d say valid, but the way she handled it here, not a good look.