I'd be really interested in an outside perspective on this as I can't decide if what we are considering is reasonable or not.
Daughter is 18, 19 this summer, and a full time student. We would like to book a holiday to the US for two weeks this autumn, to include her, her siblings and dh and I. Our daughter will only come on holiday with us if her boyfriend is allowed to come, however. We took him on a long haul holiday last year, and it cost us the best part of £2k for his share. He is a nice lad, we like him a lot, but his presence inevitably changes the family dynamic (as you'd expect, and as is possibly inevitable within the family anyway as children grow up) and he and dd argue quite a lot. There were instances on the last holiday of one or both of them storming off for hours, refusing to get out of the car at a destination, refusing to come into a restaurant etc, not talking to one another, perhaps every couple of days. It overshadowed the holiday. It's not a destination where they can be terribly independent either.
Since then we have been on a couple of UK holidays without them. She refused to come without him, I refused to take him and it caused upset. We now want to go long haul and she will be very upset and angry that we are going on a special holiday without her. However we can't afford to take her boyfriend, don't want to if I'm honest (because of the arguing, not because of him per se), and don't want to not go simply because she is refusing to come. That doesn't seem fair on her siblings.
To avoid drip feeding, she is going away this year with him - they are having a week all inclusive in Spain, a week in France, a week skiing. However that doesn't really change the fact she would be left out of the family holiday.
Would we be unreasonable to go without her?