The Secret Life of the Elusive Governess by Hanna Hamilton

Because running from the past is a race you can’t win….
Dutiful governess Miss Caroline Robins could easily recognize the handwriting on the mysterious note. Her past is catching up and it’s returned to finish what was started ten years ago.
Trapped in a loveless marriage, Moses Hayward, Duke of Barley, trudges the misty ground between propriety and his ever-growing attraction for his children’s governess.
But not everything is as it seems, and Caroline is hiding a dark secret that threatens to leave them in shambles. She’s been lying to them all.
When Moses’ daughter is kidnapped, he is given an ultimatum: in order for Josephine not to die in a few hours’ time, Caroline must die in her stead.