Monarch (Grimestone #2) by Sophie Lark-New

In a desperate bid to get out of town, twenty-seven-year-old virgin and bookstore nerd Elena Zelenska becomes the world's most unlikely mail-order bride. Her gamble pays off when she's swept off her feet by Benjamin Wittacker, handsome single father and (gasp!) actual published author. Elena's new fiancé seems almost too good to be true. Her life is turning into a fairytale, especially once Ben starts building her a castle in the woods. But when Elena arrives in Grimstone, her fairytale turns darker.

The castle in the woods is a macabre labyrinth of hidden chambers, and Ben is no Prince Charming. In fact, he might just be a monster.

Isolated far from home, Elena's only ally is Atlas Covett, the owner of the Monarch hotel. Massive and stern, even Atlas' employees are terrified of him. He becomes Elena's unexpected protector, offering solace and sanctuary from the darkness that threatens to consume her.

As Elena's bond with Atlas deepens, her jealous fiancé exerts his control in increasingly twisted ways. Elena must find a way out before the castle he's building becomes a prison she'll never escape…