The Wife Upstairs by Rachel Hawkins

In this modern twist on a classic tale, a young woman named Jane, who is struggling to make ends meet, finds herself drawn into the affluent world of Birmingham, Alabama, where she works as a dog walker. She becomes entangled with the charming and wealthy widower, Eddie Rochester, whose wife, Bea, mysteriously disappeared. As Jane and Eddie's relationship deepens, Jane uncovers dark secrets about Bea's past and the truth about what happened to her, leading to a suspenseful and thrilling exploration of love, deception, and ambition.