About Before I Wake by Mary Ellen Johnson:
Historical novelist Magdalena Moore is haunted by the black-haired, black-eyed knight she first encountered during a past life regression. Across a lifetime, Magdalena searches for the truth about Ranulf Navarre and his wife, the meek, complaint Lady Jane.
At Tintagel Castle, Magdalena is miraculously transported to thirteenth-century England, where she is Lady Jane, and Lord Navarre is her husband. But Ranulf is not the man of her imagination.
Why is Ranulf so cold and Janey so erratic? What secrets are they hiding? When England plunges into civil war, Ranulf backs the wrong side. Knowing he is destined to die in battle, Magdalena tries desperately to cheat fate, save Ranulf, and finally find happiness. But when her secrets are laid bare—or more specifically Lady Jane’s secrets—Magdalena fears Ranulf can never forgive her. And if he cannot, will they be forced to replay their doomed love yet again?