Deliverance by Victoria Danann

Choices always come with consequences.
If you force a demon to agree to a deal under duress, the day will come when you’ll regret it.

Two and a half centuries ago Sixt had been a young witch with little control. In a fit of jealousy, she’d cursed the demon with an addiction spell. She thought better of it shortly thereafter, but couldn’t find him to take it back. She did something unforgivable, but she wants forgiveness anyway.

Deliverance had been a slave to sex for so long he could barely remember life before. When he learned the compulsion that was a never ending itch was an addiction hex, he was elated because hexes can be withdrawn by the witch who casts them. But the euphoria was short lived when he learned the price he’d have to pay to have the curse reversed.