The Dark King by Gina L. Maxwell

For Bryn Meara, a free trip to the exclusive and ultra-luxe Nightfall hotel and casino in Vegas should’ve been the perfect way to escape the debris of her crumbling career. But waking up from a martini-and-lust-fueled night to find herself married to Caiden Verran, the reclusive billionaire who owns the hotel and most of the city, isn’t the jackpot one would think. It seems her dark and sexy new husband is actual royalty—the fae king of the Night Court—and there’s an entire world beneath the veil of Vegas.

Whether light or shadow, the fae are a far cry from fairy tales, and now they’ve made Bryn a pawn in their dark games for power. And Caiden is the most dangerous of all—an intoxicating cocktail of sin and raw, insatiable hunger. She should run. But every night of passion pulls Bryn deeper into his strange and sinister world, until she’s no longer certain she wants to leave…even if she could.
 
- Goodreads Summary