It's not really a holiday for him it's a religious trip that his mum wants to take and they would be gone 2/3 weeks.
We have 3 kids - teen, toddler and baby.
Some background-OH is from a different culture where there seems to be a big emphasis on alway pleasing and serving parents , his mum has been on this same trip a couple of times already and he has gone with her before when we only had eldest and were living with my parent.
He didn't even speak to me about it , just mentioned it when having another conversation "oh well I can't do such and such (with another family member) because my mum wants me to go on this trip with her"
I have to admit I did not keep my cool about it , Aibu to think they he is being unreasonable?
Not only to leave me with the kids for that length of time but also use up that much of his annual leave to do so.