Unquiet Magic - Unquiet Magic, #1

Jack Belamit has been living a nice life as a quiet, modestly affluent gay man. No obligations, no stress, and a love life consisting of casual hookups at a neighborhood bar. Now, however, Jack's father and brother have disappeared, and one of the senior Belamit's rivals is moving in on his business empire, dragging Jack into the conflict. Jack's father, however, is not just any reclusive billionaire, but an incubus, a creature that feeds on the sexual energies of humans, and his rival is the witch Anaksut, the most beautiful, and dangerous, woman in the world. Jack's inheritance from his father includes fragments of incubus magic, which he struggles to understand and control, as well as the avatar, a damaged copy of his father's personality that was accidentally imprinted on Jack's psyche in the womb.
In the past the avatar has helped Jack, but over time it has become increasingly unstable, with an agenda all its own. Jack realizes that his only hope of getting his life back on track is to work with Anaksut to find his father. Anaksut assigns Carlos Colosio to accompany Jack as her spy. Carlos was once a timid delivery driver from Guanajuato, but has been transformed by Anaksut into a satyr, a being with more-than-human vitality and sexual prowess.
With Carlos' help, Jack tracks his father and brother to a remote Caribbean island, but not before he experiences an eye-opening evening in a sex club in the Baltics, a visit to a frigid mountaintop weather station and its lonely keeper, two days on the job in a tropical bordello, and frantic sex with a sentient thunderstorm. On the island of Las Sirenas, Jack discovers that everything he thought he knew about himself and his family is wrong.
Jack has no choice but to embrace his heritage and come to terms with his feelings for his family, and for Carlos.