Even though it's talking about the statistical norm, there's something about the title of this book that's deeply objectionable. It's not pop psychology; it's barely even Anthropology Lite. It's crowdsourced opinions about relationship satisfaction, which might be interesting as a listicle, but not so much as a full book. I was looking forward to some good infographics or otherwise easily digestible statistics, and what I got was anecdata and superficially extrapolated advice with a side of percentages. A lot of it is of the "no duh" variety: happy people communicate well, make each other feel wanted and appreciated, and work on being good partners. Unhappy people tend not to do those so well.