Another strange question from me, though I'm potentially guessing that this has happened to a handful of us. A few weeks ago, in a drunken and pessimistic stupor, I had an idea of how a man finally managed to lay his school crush (both adults, obviously) for a one night stand, only to realize that, whatever affection he may have had with her quickly evaporates and escapes her condo, even if the previous night proved some sort of chemistry. I wanted to add an addendum that he goes after several women for quick one night stands, feeling no connection with any of them, and potentially having a depressed bad end at the end of the stories. But nobody cared much for it so I never added said addendum. My question is, how likely is this scenario? Having never had a one night stand (or a girlfriend) before, I can only imagine the regret one or both parties go through when waking up. But what if the person they're regretting next to, was someone they held dear until then? What is the likeliness that, you stop liking someone after screwing them?
If this is about a story you're looking to write (and not a request for general romantic advice), then my answer is: it doesn't matter how likely it is. It sounds plausible enough, so write it if you want to! How likely was Charlie to find a Golden Ticket in his 1 (one) candy purchase?
Truth be told, I was also trying to have a conversation about the topic too, but I appreciate the two cents.
What's the reason for the failed one night stand? There are countless ways to make it a disaster and shatter her image of a dream girl but you made it sound as if the one night stand is the problem itself. How does that work? If he feels no connection to the girls, wouldn't he just stop going for one night stands?
That might already answer the question. Lust? Alcohol? I guess such persons exist. Having one-night stands to have fun or to collect trophies. They might always look for a certain type of "prey" that is easy to lay. And the "prey" might be aware of it and won't invest any emotions in it. So the person might never find someone who is genuinely interested in starting a relationship. Getting laid on the first date might also not be the best way to start a relationship. (Though it can certainly work out.) I guess it heavily depends on the previous relationship and how you deal with it. Maybe it is like "I don't feel anything for you but it was fun. Might repeat that in the future." or "Damn, I was so drunk! I can't remember anything from yesterday!" Maybe you just realize that you weren't really into them from the beginning but rather into the idea of screwing them.
I concur with @gene.sis That or you/the protagonist were so excited about finally getting a date with Crush, that the date went by in a blur and then when the sex happened, it also sort of happened in a lust filled blur, because after all, this is your crush, the person you/the protagonist have been fantasizing and dreaming about for so long. Then, come morning when the lustful haze is gone and the date is done, there's the realization that maybe the sex wasn't that great and/or the date wasn't great and the two characters didn't really have a lot in common. For the more personal side of things, while I've never dated or had sex with a crush, I've "lost" crushes through moments of lucidity when I've realized I didn't really have much in common with that person or we had differing personalities or views (on life, politics, etc.), or I learned about some personality trait they had that was a deal-breaker for me. Did I also find them attractive and fantasize about the sexual aspect of potential relationship with them? Sure. But if I realized that my crush wasn't really a true match for me, and by some stroke of luck still had sex with them, then that's all it would likely be, just sex. Basically, insert any celebrity crush one might have as most of those are based on looks and random bits of their personality that is often crafted for the media.
I will not discount the possibility of it being a "we banged once, and now it's over," thing, but to go against the trend a little, once the Post-Nut Clarity kicks in, there is a chance where the protag might go "Well... it wasn't great, but maybe it we tried dating for a while...?" So that's an avenue for a story. The attempt of a relationship, and the eventual discovery of whether they either click or not.
I think this isn't an unusual experience for both men and women after finishing high school. I can't say I've ever felt this myself, but I have decided I liked someone only after having sex with them.
There might be an interesting tale of 2 friends. One of whom is like Warden's idea, infatuated up till the point of sex and then things dont live up to expectations so he's immensely let down. The other by contrast is getting it on with a different person/gender/threesomes/dom/sub/dwarf/furry/robot/elf every night and quite by chance on a seemingly meaningless encounter unexpectedly finds love. Not sure if this is all too Bronte sisters though for CHYOA.
Some guys have a Madonna/Whore complex where they sort women in to "Totally Pure" / "Totally Impure" boxes. For a guy like that, having the one night stand with his crush would paradoxically make him *less* attracted because she's corrupted herself. There's a lot of story potential there (John Leguizamo has an arc like that in the movie Summer of Sam) but it also makes him a gigantic, unsympathetic asshole, so keep that in mind.
While the scenario is possible, I think it would be VERY difficult to write it and have the man come off as a sympathetic character. The ONLY way I can see that this could play out and he doesn't look like a complete bastard is if she's even worse; for instance, if she goes all psycho on him and tries to make him her captive sex slave or something like that. But, if he just "loses interest" after sex... frankly, that's a dick move and there's just no way to justify it. Now, if you don't mind that your protagonist is a total ass-hat, then by all means write the story; it might actually be interesting to do a CHYOA from that perspective. Otherwise, you're setting yourself a difficult task.
I think many CHYOAs have an asshole protagonist, whether or not the author realises it. It's probably more common than a particularly sympathetic main character.
I disagree that this necessarily makes a character an asshole. We barely-civilized apes are not in control of our feelings; we are ruled by them. If an infatuation passes naturally, then that might suck for the other party (or even both of them!), but it can't be helped. The best you can do is have them be honest and open about their feelings, and whatever happens, happens. Also remember, people aren't always looking for long-term relationships. Sometimes you just want a one night stand, and that's totally OK. There does not always need to be a deep spiritual and intensely emotional connection between sexual partners. "He's hot" can be enough. Of course, it's a completely different matter if a character is being intentionally deceptive. Saying "Of course I love you, babe, we'll be together forever!" and such, when all you want is a quick blowjob is clearly a dick move.