Unmissing by Minka Kent

It's been ten years since Luca Colletto's wife Lydia disappeared while taking a hike. The only clues left behind were her backpack with her GPS signal and cell phone still inside. He has since remarried to Merritt, who's pregnant with their second child. The couple started a chain of restaurants and are living a comfortable life. But the restaurants are now struggling and Luca is away trying to find someone to buy their restaurant brand. One dark night, a woman comes knocking on the door...a woman that looks exactly like Lydia. All she claims to want is help to get back on her feet, but as time goes on, Merritt starts to question her motives. Why didn't she go to the police? Does she want Luca back? What exactly is she expecting them to do? And the more stress Luca is under, the more he starts to pull away. Can she keep her family together and keep her dream life or is it all starting to fall apart?

Told from the alternating perspective of both wives, the mystery starts to come together and I was totally shocked by the end. What a plot twist! I've never read any of the previous books by this author, but I plan on adding them to my TBR list!