It's more a love story than science fiction, but the time travelling is neatly interwoven in and is essential to the plot. I don't want to give too much away, but if you have a sentimental bone in your body you will love this book.
Although not the same kind of story, it reminds me of The Sparrow by Mary Doria Russell. I guess it's because I am so used to sci-fi written from a male author's perspective that a female voice seems refreshing to me. (Except for Octavia Butler, whose books I hate) When's the last time a book by Bear or Niven or Heinlein or Asimov made you cry? Nuff said.