[TOMT][BOOK] help for a friend requested.

Here is all she can remember:  "I read the book in the early 90's, the main character, I think, was hit by a car and then her life split into two stories. One life meant not marrying and the other life had her married with kids. It took place maybe in the early 1900's. One life was written in normal text and the other in italics. At the end her two lives merge or cross somehow and she meets herself. It's been driving me crazy! "

If anyone has any ideas I will let her know.

Thanks all