What strikes me about this is that this guy thinks he is entitled to have some fun at a really crucial point in your lives together.
This entitlement for 'fun' seems to be a mainstay of many men. Women don't need fun, right? Are they even capable of having fun?
For some men, it isn't that they conveniently forget that women like to have fun, hobbies, no responsibilities, holidays, laughter etc. It's that those men genuinely believe, really deep down at a level that couldn't be reached even by a military-trained psychiatrist, that women don't want fun, or need it. They are fulfilled and satisfied by becoming mothers, by creating a home, by keeping the home running, organising clubs and activities for their children, helping with homework, cleaning the toilet, walking the dog.
And so those types of men feel this leaves plenty of space for them to take up time-consuming hobbies, like golf or cycling or training for a triathlon. Or going to Ibiza With The Lads because you're Ruining His Life (did you marry Kevin from Kevin & Perry?) and he wants to Have Fun and you just don't understand.
Of course, the timing means you can't have Ibiza fun right now Op because you're physically unable to - heavily pregnant, vulnerable, can't go on a bender, but it doesn't mean that you've ceased to exist as a PERSON. You still have wants and needs. Imagine if you were trying to arrange a last-minute trip on a hen's do to Ibiza at 38 weeks pregnant (suspending the fact that you wouldn't be able to fly for a second). What would he say? What would his reaction be? Laugh it off, initially, and then as it dawned on him that you were serious... Incredulity? Eyeing you up, pregnant tum and all, and thinking, 'how massively irresponsible. How selfish.'
What about later, when the baby's here and you're sleep-deprived and haven't had a shower and just need a break. Is he off down the pub? Or is he saying you need to shower and get down the pub with your friends and have a break? My money's on the former.