Yikes! No, I don’t think you’re at all in the wrong, Ver. She sounds like someone who needs an information diet… You say the parents give her whatever she wants, but would they go as far as to take her side in this? That would be my concern.
She also doesn’t get to dictate what you do on a vacation after her wedding is done. Maybe this is your plan already, but if I were you, I’d find a separate hotel to go to after the destination wedding is over. There’s less of an argument for her to make if you’re leaving the hotel along with everyone else (and I’m sure you won’t be the only ones making the destination wedding into a longer vacation, I feel like that’s pretty common).