I seem to remember discussing this book already somewhere. Probably on Scott C's blog. It seems my (entirely negative) impressions were pretty well founded. I think we, as a culture, still generally value honesty fairly highly. Thus I would be surprised if "cheating", in the sense of dishonesty, was really significantly increasing. On the other hand, we do not seem to value constancy at all, so I'm sure that in the sexual realm cheating has been increasing over the last several decades.