A Demon's Choice. Demons Hearts, #6

Harrison is fascinated by Salomon, the demon who helped save Ilyhas and Esi's lives. He isn't sure why, but it doesn't matter since he's never going to see him again-until he does. Sal is still trying to identify the demon who cast the spell that almost killed Jadon's boyfriends, and he needs Harrison's help. Sal hates not doing things by himself, but he can't go into a human building to find the demon, not when he's obviously not human.
He's not sure Harrison will find something, but he does, and much more than Sal expected. Sal's ex is the demon involved, and she's still angry with him for leaving Hell. When she locks his powers, he knows he has to follow her back to Hell, no matter how little he wants to. He hadn't counted on Harrison coming with him, though. Harrison knows he should stay home, but there's no way he's letting Sal face this without him, even though he's not going alone.
Hell can be deadly for humans, but he's more focused on getting Sal's powers back-and on falling in love with him. But not only is Hell deadly, so is Shaila, Sal's ex, and she's still holding a grudge that's going get all of them killed.