If you are looking for a really good read, then I highly suggest Switcheroo by Olivia Goldsmith. She is the woman who wrote The First Wives Club.
Switcheroo is not your normal everyday basic romance novel. It is oddball and quirky. There is tons of comedy in it.
The premise of the story is that Sylvie has been married to Bob for over 20 years. Their marriage has gone stale. Bob starts seeing Marla on the side. Sylvie finds out and confronts Marla. Only to find out that Marla is a younger version of herself. They look exactly alike except for Sylvie looks older.
Marla wants to be a wife and Sylvie wants to find out what it is like to be the bit of fluff on the side. Chaos ensues as they attempt to switch places.
Believe, this is definitely a must read.