Gentleman Sinner by Jodi Ellen Malpas

Izzy White knows of the darkness in this world. After all, she escaped it long ago. Determined not to let her past beat her, Izzy has a secure, stable life with a job she loves in nursing. But one act of kindness will completely upend everything she’s so carefully built-putting her right back in the crosshairs of danger she’s been so desperate to avoid.
When Theo Kane shows up like a knight in shining armor, Izzy can’t help thinking she’s been saved from one threat and exposed to another. His imposing physique, the harsh lines of his face, and the wariness of everyone who comes close are just a few clues to Theo Kane’s notorious reputation. The man is positively terrifying. But with Izzy, he’s tender and a complete gentleman, and her fascination with the mysterious beast of a man becomes too powerful for her to walk away.
As Theo’s demons come to light, running becomes even more impossible. And yet staying together could doom them both.