LM Brown - Between Good & Evil (Heavenly Sins #2)

Tristan's demonic bargain and the repercussions following his decision to enter into it could tear apart forever the ménage he and his angel and demon lovers have formed.

Tristan, Machidiel, and Alastor are bound together by love, but their lives are running far from smoothly thanks to Tristan's demonic bargain with an incubus. Tristan has two choices, remain with the incubus as his trainee or find a mortal to take his place. Neither choice is appealing.

The three lovers struggle to release Tristan from his bargain, only to find bigger problems on the horizon when a human caught up in the mess is taken prisoner by the Demon King himself, with repercussions that could tear their ménage apart forever.