Your partner, and the honest gap in the evidence
Nobody has studied what a birth that went differently does to partners. That is not the same as knowing they are fine.
Partners watch the whole thing and are asked about none of it.
The systematic review of what happens when a birth is not as expected looked for studies of the effect on partners or on babies. It found none. Zero studies. That is worth stating plainly, because absence of evidence gets quietly converted into reassurance, and here it should not be.
What exists is an estimate rather than a measurement. The authors of a 2024 clinical review estimate that childbirth-related post-traumatic stress affects around 1.7 million fathers or co-parents worldwide each year, alongside 6.6 million mothers. Those are modelled global figures, and how they were built has not been verified here, so treat them as the authors' estimate rather than a count.
Practically, two things follow. Your partner may be carrying something from that day that nobody has ever asked about, and may be avoiding raising it because it does not feel like theirs to claim. And a partner who was frightened during the birth may be more, not less, likely to minimise your account of it, because agreeing with you means going back there.
"Is there anything you saw that I do not know about?"
"I need you to hear that it was bad for me, even if it was not bad for you."