THE STORM by John M. Wills
The heroine, Anna, is out for a run in a secluded area and is struck by lightning during a sudden storm. She isn't discovered right away, and when she awakens in a hospital, she has no idea who she is.
Her husband, Mark, who has been unfaithful, regrets his actions. The woman he's been seeing isn't ready to let him go and causes major problems as he tries to help Anna recover from her injuries and to regain her memory.
As with all of John's books, there is a spiritual element.
When it doesn't seem like things will be resolved in a happy ending. there is a shocking twist.
I did enjoy The Storm, and recommend it to others.