I think you're right. I'll keep it in mind for the future.
I feel stupid now and like I messed up by waiting a few days to figure out if our plans were set.
I also feel like if it were XW's weekend, I would have told her something like "hey, did you know Disney is in town this weekend? I bet D would love that" rather than saying "Hey, Disney is in town and I want to take her, let me have Saturday"