Superheroes are a sexy bunch, there's no doubt about it, but having sex with a superhero seems like a task best left up to other superfolks.
For our normal human bodies are fragile, and probably wouldn't be able to withstand a physical encounter with some super strong, super fast and/or super thick skinned individual.
But if you're trying to get down and dirty with The Thing you might find him too embarrassed to return your advances- because the jury's still out on whether he has functional genitalia in his non-human form.
On the other hand, Rogue of the X-Men is anatomically correct, but touching her bare skin can cause power loss, permanent memory loss or death. She's hot but she ain't that hot!
Read The Creepy Downside Of Sex With 6 Superheroes here (NSFW language)
Larry Niven addressed this 40 years ago, "Man of Steal, Woman of Kleenex."