A Demon in Waiting by Holley Trent

Ariel Thomas has never been prone to reckless behavior, so picking up a gorgeous man from the roadside during her cross-country drive is totally out of character. She’s usually the kind of woman who keeps her doors locked and mace at the ready, but something about the stranger gives her the kind of goosebumps she doesn’t want to go away.
Incubus John Tate is new on the job and totally out of his element. Secluded for twenty-eight years in a desert cult, he never knew his true father, Gulielmus, was a demon. When Gulielmus offers John freedom, John follows. Tainting souls seems a small price to pay in exchange. But when his first target turns out to be a sweet, quirky woman who’s as open-minded as he is inquisitive, his plans fall to the wayside.
John doesn’t want to corrupt Ariel—he wants to be kept by her.
John knows that having his father for a direct supervisor means there could be harsh penalties for insubordination, and Gulielmus wants him to seal the deal with Ariel’s soul or else move on to the next victim.
But how can John do that when she’s managed to entrance him even more than he has captivated her?