I think that “asking permission” thing is rubbish. But there has to be a way of talking about things that means a proper decision can be made without anyone feeling either put upon or disgruntled?
Well, of course there is! When your partner is a mature individual. My spouse and I have hobbies that both involve, ideally, time away. Our kids are now secondary school age, one teen and one tween. And even now, of course, it's, when the opportunity arrives, considering both peoples' work schedules, leave, the needs of the children, the need for equal time out and costs, managing around family time, too. That's just life when you choose to have children and they are not grown up.
The problem is that this person hasn't considered any of that, just expects the other parent to give a green light and cover all the rest or they sulk and cry 'Fun Police!' The child in this instance is very young and requires childcare that needs to be covered in school holidays but taking leave from work and in this instance, as the OP states, he wants to use all of his leave in one block to completely excuse himself from any childcare obligation, much less a family holiday or time on his own with his child.
We've all been there, hobbies can be tricky when you have young children, but as my father always said, 'If you want an easy life, don't have kids.'
Personally, yes, I've had to turn down 'opportunities of a lifetime' in the past because they wouldn't fit with the family I chose to create with my husband, which is in itself also an opportunity I could have declined, and he has had to pass on some things, too. Now they're a bit older, there's more leeway but we still consider the impact on each other and the whole family before even bringing it up. I mean, that's just basic adulting, I'd have thought.