I think the idea of the book is good, time traveling, a man and woman separated by the man's inability to stay in present time. A love that transcends all, including time travel. I get it. However, the book jumps around so much between time periods, that even if the idea were plausible, the plausibility is lost with the frequency in which the man time travels. Not too mention the drama that the woman has to put up with given the actions of the man while he time travels.
I think the skeleton of the story is good, I just don't feel like any particular event or plot in the book goes into enough depth to make you feel like the book is worth reading. I felt as though it was written very "high level" without enough details to backup the point. To me it read like short stories and not a novel.
Maybe someone else will think differently or have more to offer. Maybe I missed some great point. But really, it's just a love story that isn't written with enough steamy details or enough depth to be really taken seriously.