“The French are much more comfortable with the idea that their affair partner is just that—an affair partner,” writes Pamela Druckerman in her cross-cultural look at infidelity, Lust in Translation.

Love is not breathlessness, it is not excitement, it is not the promulgation of promises of eternal passion. That is just being “in love” which any of us can convince ourselves we are. Love itself is what is left over when being in love has burned away… —Louis de Bernières, Correlli’s Mandolin

anatomically modern humans are estimated to have existed as long as 200,000 years.* With the earliest evidence of agriculture dating to about 8000 BCE, the amount of time our species has spent living in settled agricultural societies represents just 5 percent of our collective experience, at most. As recently as a few hundred years ago, most of the

They note that the absence of sexual desire is the most common sexual problem in the country.30 Combine these dismal numbers with the 50 percent of all marriages that end in divorce, and it’s clear that modern marriage is suffering a soft-core meltdown.

Novelty itself is the attraction. Though

“Since Darwin,” she writes, “we have assumed that humans evolved in families where a mother relied on one male to help her rear her young in a nuclear family; yet…the diversity of human family arrangements…is better predicted by assuming that our ancestors evolved as cooperative breeders.”

Our bodies echo the same story. The human male has testicles far larger than any monogamous primate would ever need, hanging vulnerably outside the body where cooler temperatures help preserve stand-by sperm cells for multiple ejaculations. He also sports the longest, thickest penis found on any primate on the planet, as well as an embarrassing

If you spend time with the primates closest to human beings, you’ll see female chimps having intercourse dozens of times per day, with most or all of the willing males, and rampant bonobo group sex that leaves everyone relaxed and maintains intricate social networks.

True, as far as it goes. But it doesn’t go very far, because Smith forgets that our ancestors were the original ramblin’ men (and women)—nomads who rarely stopped walking for more than a few days at a stretch.