Kiss of a Demon King by Kresley Cole

Sabine, Sorceress of Illusions: the evil beauty who surrenders her body, but not her heart. Rydstrom Woede: the ruthless warrior who vows to keep her at all costs.

With each smoldering encounter, their shared hunger only increases. If they can defeat the sinister enemy that stands between them, will Sabine make the ultimate sacrifice for her demon? Or will the proud king lay down his crown and arms to save his sorceress?