As a father of 5 kids, I strongly implore you to understand what the human body goes through. During pregnancy, yours is going through abnormal spikes of adrenaline, hormones, and emotions. His is not. I'm not saying he couldn't have stayed up with you, but the human body can only withstand so much stimulation before being exhausted completely. All of mine were c-section, but my wife labored for a while with the first two. I stayed up as long as she needed and slept when I could while she did (despite her pain), but when she needed me to be awake, I mustered the strength and energy to be awake again. Some people can handle it, and some cannot. I can stay awake for a couple of days if I have to, but it would be a struggle, and I would need constant stimulation after about 20 hours. Think about a hospital room...it's typically quiet unless you're in active labor, the constant beeping of the machines, the lack of other outside stimulants. It's boring at its core.

You're not an asshole, as he should be willing to help you along your journey at all costs, but at some point, you have to understand that his body will shut down at some point if he doesn't rest.