I dunno, I more often see this phrase combined with masturbation to porn the user cannot believe they masturbated to afterward. There is a sense of clarity following ejaculation, but it doesn’t necessarily have anything to do with a sexual partner or their perceived attractiveness.

Edit: I’m a little sad that people are downvoting you. To be clear, I think your explanation is just as valid as mine. Just because my experience with the phrase is different doesn’t mean your explanation didn’t add to the conversation, and I liked reading it.

Post-nut clarity is not just for the straights. You can get PNC after fucking other dudes, or even after fucking one’s self.

Ive always thought of it as more of a shot against the man than the woman. In your example, the man slept with someone he normally wouldn't, for whatever reason, and only recognized that fact once his desire for sex was satisfied. The woman didn't change in the entire situation.

Likewise, I'd say my choices in this area were poor, but had nothing to do with looks.