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.