Release Me — Nina Croft

A thousand years ago, Finn Stanton was given a chance to get back the woman he loved enough to break the laws of Heaven. All he has to do is find her, and all she has to do is say I love you.
Never going to happen.
Having drunk of the Elixir of Life, Rachel Miller's soul is tied to the earth in a perpetual cycle of death and rebirth. A widow, she lives with her six-year-old son in a strict religious community. She has no memory of the lives she has lived, though she is haunted by a love she can't remember and a loss she can't overcome.
Finn has no plans to even look for his wife. He betrayed her once, and the best thing he can do for her now is stay away. But fate has a way of hijacking the best of plans and Finn comes face to face with Rachel. Now he has five days before he loses her forever.