ExH works like a dog, when we were together he was gone by 5am and home by 9pm most nights and would still do work.
It was the major reason we divorced.
He's a nice bloke, but trying to pin him down is practically impossible. We have 2 DD together, 10 and 8 and if he's going to show up, I get a phone call or a text a few hours before hand and then he whisks them away for the day, which they love but is honestly annoying. He does this at least once a month.
We've only been divorced for 2 years, so this is only our second summer.
Last summer the girls were in play schemes/camp and with grandparents and he took them out a handful of times, I assumed this summer was going to be the same but without any warning whatsoever, DH has taken 2 weeks off work.
This is the same man that went to work half dead with a cold, shivering all over the place.
I was delighted, asked for the dates so he could have more then just a day with his Daughters and surprise surprise he's booked them all a holiday without asking/informing me that clashes with camp and a play scheme
The Camps cost a little over £600 per child and the playsheme is £35 per child per day for 6 days, that's £420, all together that's cost me a little over £1600 
I said that it was fine if they went but that he would have to reimburse me the money for the camps and playsheme that they would miss as it's too late to get a refund, he argued that I should take it out of the Child Maintenance he pays 
He pays £500 a month, £250 per child, that's all he financially contributes, it would take months of his CM payments to cover the loss!
AIBU to think he should reimburse me? And if I'm not how do I get him to do it?!