Salt Kiss by Sierra Simone

After being a soldier, working as a bodyguard should have been simple: keep the owner of DC’s ultra-secret club safe, don’t think about his midnight eyes or his devil’s smile, don’t surrender my body to his wicked desires.
But I underestimated Mark Trevena and the power of his dark, seductive world. I underestimated the hold he’d have on me, the way I would do anything for him at all. And so when he asks me to escort his soon-to-be bride home, I can only—miserably, broken-heartedly—say yes.
Isolde is nothing like I expect, however. Quiet and lonely and sharp. A girl who likes knives and God. A girl whose nightmares echo my own. And one night while sailing under the cold stars, we share a reckless, tear-soaked kiss.
I’m doomed. Falling in love with Mark was one thing, but his bride too? Being in love with a husband and wife at the same time?
Torture. Misery. A tragedy if tragedies came with bruises, sweat, sighs.
But it isn’t enough to merely fall into the forbidden.
Because in Mark Trevena’s world, the fall is only the beginning…