I thought some of this was interesting. I've often commented to Gary that people are being fed the idea that feverish honeymoon neurochemistry is perfectly sustainable and "normal" throughout life, which leaves many feeling dissatisfied and victimized, and as if their needs aren't being met, once those temporary honeymoon-rush neurochemicals return to base levels. (Moreover, today's porn can easily "inflame" peoples' neediness, such that no one human could ever meet it, and yet most sexologists assure them that this isn't happening, and that they are just "exploring their innate sexual tastes" as they hop on the escalation treadmill in their porn use.)
In any case, dissatisfaction due to seeking perpetual honeymoon passion was certainly my experience. The fact that I so strongly valued pair bonds is what sent me on my quest (that resulted in Cupid), but kids who don't have strong pair-bond models can easily not see sustained pair bonds as a target at all. In any event, no one was more surprised than I to discover that the answer was to get my foot off the accelerator in a sense.
As for the orgasm chapter, and I am very glad to see he acknowledged that sex without orgasm isn't a pathology! This indicates a break from standard sexology fare. Did Garcia read Cupid??
There are three important points, I think, from the book:
1. The extended duration of contemporary 'adolescence' - sexual maturity it a younger age and delayed parenthood, especially motherhood, compared to the past. This also means there is a powerful youth culture which is a massive consumer demographic related to sex and sexual competition/sexual attraction.
2. Ancestral females would have been pregnant or lactating much of the time during their fertile years, vacillating between intensive offspring care and mating - with much variation in libido and sexual behaviour. Most sex was within long-term partnerships and male sexual behaviour would track women's sexual and reproductive 'ups and downs'. Few unpartnered, childless women. Women rarely fertile due to pregnancy/lactation, and sex within the pair-bond for maintaining that bond.
3. Life-history - shifting priorities through life stages connected to sex and reproduction = sensible adaptive adjustments which enhanced lifetime reproductive success.
Much of the evolution-oriented work on human sexuality focuses on the emerging adult (ie college age) mating strategies, but sexual priorities can wax and wane during reproductive years based on female cyclical processes.
Their chapter on orgasm:
Variation across cultures in eg extent of foreplay. Modern contexts are likely novel ie in the past most sex within long-term relationships and few potential partners. They mention Tantric sex and the avoidance of ejaculation but that prolonged sex was likely uncommon in the hunter-gatherer past due to the proximity of others. The celebration of sex as performance for pleasure may be relatively recent.
They write about the models of sexual response - Masters and Johnson, the Kaplan model, and Janssen and Bancroft's dual model: excitement and inhibition.
Sex differences in erotic plasticity and women more responsive to environmental and social cues. They point out the overlap between the sexes and the individual variation.
They write about the distinction between genital arousal and cognitive arousal and the discrepancy between physiological measures of arousal and subjective experiences (Janssen's "Psychophysiology of Sex" 2007, and work by Chivers and Bailey).
Physiological responses to sexual stimuli need not represent desire or consent, eg a male receiving fellatio may have an erection and orgasm whether receiving it from a man, a woman, or a nonhuman animal.
They mention brain scans during orgasm - Komisaruk and Whipple.
They end saying that plenty of people enjoy sexual activity without experiencing orgasm and that a number of cultures prize the ability to have prolonged sex without orgasm.
Both sexes (and particularly women) are more likely to orgasm in a committed relationship.