It makes sense from a why standpoint. I can’t help but wonder about the how.
How did we evolve reproductive organs that are not only sensitive, but also release reproductive cells at climax?
I’m ok with a “we have no idea” answer, but if there is an answer I also want to know.


Quite a few things about the reproductive process can feel bad. Ask any woman with a yeast infection or any guy with an exposed wound on his genitals (perhaps from an STD). The sexual drive is more than just the superficially sensual. And very few organisms are documented to experience the kind of chemical release associated with it, despite all of them engaging in reproductive activity.
The orgasmic release has a long-term social role, encouraging pair bonding between partners and inhibiting aggression in the male immediately afterwards. So maybe less an incentive to have sex and more an incentive not to kill your mate when you’re done.
As in nobody’s looked, nobody can tell, or there’s demonstrably an absence?
Animal reproduction is exhaustively researched.
Some parts of it. If you want to know about bird mating dances, you’re set. If you want to know something more specific, or about an unpopular taxon, you might not be. You said “very few animals”, implying this would be true for nearly everything that’s not a human.
Without more information, it seems like the kind of data that would be available for a couple lab workhorse species if anything at all, since it’s brain- and subjective experience-related.
Cue the “my wife wants to kill me whenever we get done having sex amirite boys? Herpaderpaherp!” boomer hoomer hehehe
Horniness is a weird thing. You’ll climb over rusty nails for sex even if you don’t get the Big O with any reliability.