Dark Horse by Maggie Rawdon

Grant Stockton is the devil incarnate. The cowboy turned casino-owning crime boss has been the bane of my existence for as long as I can remember—first as my older brother’s best friend, then as my guardian when my brother died at his side, and now as the rival bar owner and landlord running me into the red.
He might be the head of The Quiet Horsemen, the man everyone else in this town fears, but I’m not about to cede a single inch of ground to him.
If I have to lie, cheat, and steal to keep him from finding out my bar’s underwater—well, that’s exactly what I’ll do.
At least until he breaks into my apartment and discovers my secret. One that gives him all the leverage he needs to control my fate.
My only reprieve is that The Horsemen are in the middle of a war, one that’s been spilling blood for the better part of a decade, and his enemies are closing in on our small mountain town.
Which is why I’m taken off guard by the demand he makes in exchange for keeping my secret.
Apparently there are benefits to being at the mercy of the devil…