The book largely takes place in the span of a day. The point of view switches back from the husband and wife. Both spouses are keeping a secret from the other one, but they don't want to ruin a party for each other so they keep them to themselves. Meaning 95% of this book is switching back and forth to the thought processes of each character. Maybe fun at first. Then highly annoying.
Each section plays out like this: Husband: Keeping this secret is so hard. I need to tell my wife. I'm going to tell my wife. But she looks so happy/this is the last time she'll be happy/this is what she'll think/etc. I can't tell my wife. Switch to the wife, same internal dialogue. Rinse. Repeat. x100.
I enjoyed the first couple of books by this author but I don't think I'll read her material anymore. These books make me incredibly frustrated by my own relentless curiosity. I can't put it down because I want to know how it ends, even though the book is incredibly exasperating more than suspenseful. So much could be resolved with conversations between the characters but that would be a much shorter book.
2 stars was generous and only because I actually made it through to the end of the book without throwing it across the room (see Nicholas Sparks).