A very short book about a very interesting topic, how the writer managed to make it seem long and boring I have no idea.  I personally think the biggest issue for me was expectation, I thought it may have included some first hand accounts of both sides of an affair.  Unfortunately it’s quite a dry summary of all the possible reasons the writer thinks a person may have an affair (not taking into account any innately malicious reason) and why it’s always both parties fault.   Ultimately I think this lacked interest, real examples and emotional nuance.