Our hero had finally managed to capture one of his enduring nemeses, an attractive female known for her wiles, as well as some superhuman strength, speed, and agility. He is unable to immediately turn her over to the authorities, though, as they do not have a location to hold her at, at present, so he restrains her in his secret base beneath his home. What he is unaware of, though, is that she also has limited telepathic abilities, capable of exerting mental influence on those who are in distorted mental states, such as sleep or euphoria. As he sleeps at night she fills his mind with erotic dreams of her, at first making him reluctant to turn her over to the police, and eventually causing him to desire her, to take advantage of her as she is restrained in his lair. Each time he takes her, her control over him grows, until he becomes her sex slave.
This is just a rather general outline, and more precise details could be worked out, it could be interesting to have him married to a woman unaware of his heroic habits, or other things like that. I have a predisposition to want to play the villainess, but would be willing take the reins of the hero if necessary. Could be done with genders reversed as well.
As an alternate idea the scenario could play out similarly with a villain capturing a superheroine, either her slowly working him over to get him to release her, or he could be the one with mental powers, taking control of her as he takes advantage of her.