The Captive’s Curse by Eliot Grayson

Unwanted. Unloved. Unransomed. And unable to control his dawn magic by any other means…

At odds with his family and on the run, Lord Cyril is taken prisoner and held in a gloomy mountain fortress—which he brightens up quite a bit, thank you. His captor wants him to be quiet and not cause any trouble, but who cares? Cyril may need the mysterious highwayman to quell his dawn magic and keep him sane, but he’s overbearing, sardonic, and unpleasant.
Mostly. Except when Cyril can’t live without his touch, or his voice, or his rare smile…
Ser Enzo, a robber and (not quite) a gentleman, desperately wants his obnoxious, adorable, irritating, irresistible captive off his hands…and other parts. Lord Cyril’s wanton, irrepressible, and worst of all—his family won’t take him back. Enzo can’t release him without being paid. It’s against his principles.
But so is keeping his bewitching captive forever. Cyril may be his prisoner, but Enzo’s dangerously close to losing his own freedom by falling under the mage’s spell…