Sparks of Blue. Dark Light, #2

Nearly a century ago warrior angel Kai and Nephilim Belle were lovers. Then he broke her heart and never looked back. Now Second in Command of the angel armada, Kai knew he was the obvious choice for this long-term mission. And his job was clear: keep Belle and her patient alive. But he wasn't prepared for the resurgence of old memories and long-ignored feelings. He'll have to face what he did a hundred years ago if he wants a chance to be back in Belle's arms.but even then, angels are forbidden from laying with Nephilim.
If they're caught, Belle would be executed. Born a Nephilim, Belle was neither angel nor human. But she was a healer, and she was damned good at it. Her reputation got her noticed by the armada and eventually earned her the title of Master Healer. It also earned her a terrible assignment: save the life-and therefore the soul-of a cursed human.under the protection of her ex-lover. And it turns out the chemistry they'd once shared may have been buried, but it's a flame that could never burn out.