The Chemistry Between Us: Love, Sex, and the Science of Attraction

by Larry Young

Sixteen percent of American married men age 40 to 49 said they have sex “a few times per year to monthly” in a 2010 national survey conducted by the Kinsey Institute for Research in Sex, Gender, and Reproduction. Only 20 percent of married men age 40 to 49 said they have sex “two-to-three times per week.” Thirty-seven percent of married men age 25 to 29 (and presumably married for a shorter period of time) said the same. Women showed similar trends. Many factors affect sexual frequency and motivation, including children, work, bills, and how fit and healthy you are, but there’s little doubt that the falloff is neurochemically based. Married men have significantly lower testosterone than single men, just like the marmosets. They have higher estrogen and lower stress hormones. They are bonded and settled. They give back rubs that are just back rubs. Living with somebody for a long time diminishes our interest in having sex with that person. It’s sad, but true.