It can be awful for the children involved. My exH makes our dc feel like an inconvenience - he hates reading the same books/watching the same programmes with (ASD and learning disabled) one dc, and has openly said so to them. He finds it boring, apparently.
He doesn’t arrange to do anything or take them anywhere during school ho,idays, but is also very keen to carve out his separate holiday time, away from the dc (and therefore shortening the amount of time he can see them, due to annual leave restrictions) as he ‘needs’ a holiday.
The dc feel unwanted, and another poster put it well when they said it’s about control and guilt. It’s utterly shit of him, but he’s not going to change now.
With the going back to school after the holidays thing - we all love a break, and I do lots of trips with the dc, but after the summer holidays especially (my youngest had nearly 10 weeks last summer!), we are all looking forward to school starting again, just as much as we were looking forward to school breaking up! The dc look forward to seeing their friends again - they see them in the holidays a a bit, but not the same groups/not all of them - and getting back to the bits of school they enjoy (eldest loves getting back to baking and gardening groups, middle loves getting back to music and drama groups, and youngest looks forward to computing and art - all things that can be done in some way at home, but delivered better by school and in groups).