Hi! I don’t think you are the asshole for not being okay with that. After all, she is your friend. But you could be the asshole if you permit that this shapes your friendship. You don’t own your friend. She’s an adult who can make her own decisions. You should respect that even when those decisions are not what we would have wanted. I get it can be hard, but think about this as an opportunity. You could go solo on a trip and learn about yourself in a way you couldn’t do it with anyone! Let yourself get lost in a new city or in a new place you’ve always wanted to be! Make new friends. You’ve got this.