Not my business, I know... But she told me and I'm 
My friend is a primary teacher, and her BF/DP and her are planning their (first, as a couple) holiday in the summer. As she's a teacher she can only go during school holidays.
Her BF has a more normal job with shifts, fewer weeks of holiday but obviously can be a lot more flexible than her about when he can take them.
Because they want to go on holiday together, they have to go when she is off and it will cost more. So between them they have rationalised that it's fair if she pays the difference between what it would have cost him to go in term time to the same place.
I didn't ask the cost difference as I was struggling to formulate words.
She seems to think it's fair enough, as he'll be a lot more out of pocket because of her. I think WTAF. I doubt it's a difference of 50 quid, probably hundreds (they're going abroad)? She seems to really like him 
HIBU, isn't he?
I can't be alone in thinking that this is a VERY unattractive trait? Or is this fair and I'm being harsh?