The Dangerous Passion: Why Jealousy Is as Necessary as Love and Sex (28 page)

“Oh, Christ, I could write a book! Ah, comparatively, he is a
fantastic lover . . . The physical thing, you know, between Jim and I is
absolutely incredible. It’s probably—it’s the major thing even with all this
intellectual closeness, it’s primarily, you know, a good fuck . . . He has really
opened me up as a lover even more than my first. I do things with him that I
can’t do at home.”

“Sexually it was really great for me. He was more sexually
satisfying, more physical. I was more physically attracted to him, I was just
absolutely in love with his body.”

“Our sexual relationship is totally different. I guess that’s
where the crux of it is. It’s certainly where it initially was and although all
other things with Peter are wonderful, it’s still the main drawing card to stay
involved in the relationship. I’m orgasmic with both. Sex with my husband is
straight fucking and oral-genital contact which is all nice, but it’s not
passionate. It’s pretty much all we do. My husband and I almost never, ever
kiss. There is little time spent in bed before we fuck. We don’t fuck very
often . . . It’s not really a turn-on like it is with Peter. I think Peter is
the greatest lover in the world. That’s obviously subjective, but I will bet
that other women who’ve made it with him will say that, too.”

When Heidi Greiling and I began to interview women about their
affairs, one prominent theme emerged repeatedly: sexual gratification. In our
very first study of women’s perceptions of the benefits of affairs, sexual
gratification was at the top of the list. Our initial sample of 90 women judged
it to be “highly likely” that a woman would receive sexual gratification from
an affair partner, more likely than any of the 28 potential benefits in the
initial study. When we asked women to evaluate which circumstances would be
most likely to open them up to an affair, sexual unhappiness with regular
partners loomed large: “my current partner is unwilling to engage in sexual
relations with me”; “sexual relations with my current partner have been
unsatisfying for a long time”; and “sexual relations with my current partner
are too infrequent for me.”

Moreover, women rated experiencing sexual gratification with an
affair partner to be one of the most important benefits of an extramarital
affair. Orgasms in particular seem especially important, as women rate these as
more beneficial than merely receiving sexual gratification.

Our exploration was motivated in part by a theory of female
orgasm that may provide an explanation for the importance women place on sexual
gratification with an affair partner, the “sperm retention” theory proposed by
two British biologists, Robin Baker and Mark Bellis of the University of
Manchester in England. To understand the sperm-retention theory, we must
introduce the broader theory of sperm competition.

Sperm competition occurs when the sperm from two different men
inhabit the woman’s reproductive tract at the same time. Although the woman’s
egg, once ovulated, is only viable for 12 to 24 hours, men’s sperm have a
longer shelf life. Sperm can remain viable within the woman’s moist tract for
up to seven days. The upshot is this: if a woman has sex with two different men
within the span of a work week, then she sets the stage for the men’s sperm to
compete with each other in the race to her valuable egg.

Is there any evidence that humans have a long evolutionary
history of sperm competition? The answer now is a resounding yes, for both
men’s and women’s physiology and passions have been adapted to the demands of
sperm competition. One source of evidence comes from studies that attempt to
determine the rates of “misidentification” of the father. Averaging across a
handful of studies of paternal discrepancy from Europe, Africa, North America,
and Oceania, Baker and Bellis estimate that roughly 9 percent of children have
genetic fathers who are different from those who believe that they are the
father. A medical researcher I interviewed confirmed this estimate. She
conducted a large-scale study of the genetics of breast cancer that required
DNA fingerprinting of children and their parents. Although it was not the goal
of her study, she calculated the incidence of mistaken paternity and found a
paternal discrepancy rate of 10 percent—findings she did not publish because
she feared that her grant funding might be jeopardized. These surprising
statistics tell us that women sometimes conceive and bear children by men who
are not their husbands, and probably have done so throughout human evolutionary
history.

Physiological clues also betray a long history of sperm competition.
First, men’s testis size and sperm volume are far larger than those of the more
monogamous primates such as gorillas or gibbons. This clue suggests that men
have evolved a larger ejaculate to increase the odds of successful competition
by crowding out the sperm from competing men. Second, men’s sperm come in
several predictable shapes, not merely the government-issue conical shape sperm
that are designed for swimming speed. As discussed in chapter 1, men possess
“kamikaze” sperm, coil tailed and terrible at swimming, that have been observed
in laboratory studies to wrap themselves around competing sperm and destroy
them while simultaneously self-destructing. Furthermore, these sperm appear
designed to position themselves within the female reproductive tract to
interfere with the progress of their competitors in the race for the eggs.

The early work on sperm competition often emphasized the male
arsenal, with women more or less passively setting the stage for the battle.
Recent work, however, has focused on the active role that women play in
influencing the outcomes of what has variously been described as a “lottery,” a
“race,” and more ominously a “war.”

Imagine taking a field course in biology in the exotic location
of Calahonda, Spain. You are grouped with 50 undergraduate students, eight
graduate students, and three senior instructors. The sex ratio is slightly
biased—more men than women. You’ve left your regular partner behind, hundreds
or thousands of miles away. You sleep under the stars on a flat roof of the
villa, along with everyone else. The brilliant beaches, azure days, and starry
nights provide a romantic setting, as you work side by side with others in the
group exploring the mysteries of life on earth. This was precisely the setting
for one of Robin Baker’s studies, and human nature being what it is, romances
often developed as the memory of the partner at home faded with the sunset.
People shared their exotic experiences with new partners.

According to Baker, women’s concealed ovulation is among the
major weapons women have evolved to shop around for superior genes for their
children. By concealing ovulation, women made it more difficult for a regular
mate to guard them during their more fertile time of the month. Concealment set
the stage for sperm competition, giving women the opportunity to be fertilized
by men of their own choosing.

In the Calahonda study, 37 percent of the 57 women arrived in
Spain without their regular partner. Of these women, 21 percent ended up having
an affair. Given that the field course lasted only two weeks, this rate of
infidelity is unusually high. Perhaps women drawn to a field course in biology
in such an exotic location might differ from women more likely to stay at home.
Or perhaps the romantic locale, combined with the distance from their regular
partner and the low risk of discovery, led to the high rate of infidelity.

Two factors predicted whether mated women would have sex with a
new partner: symmetry and length of relationship. Women who were more symmetrical
tended to stray more than women who were less symmetrical, perhaps because they
were judged to be more attractive, and hence had greater opportunities. And
women in longer relationships tended to remain more faithful than women who had
been coupled with their distant partner only briefly.

One of the most startling findings to emerge from the studies of
sperm competition, including the surveys and the Calahonda study, centers on
women’s sexual orgasm, one of the factors most closely linked with women’s sexual
satisfaction. Women have more “high sperm retention” orgasms with their affair
partner than with their regular partner, as indexed by the amount of sperm
contained in the “flowback” collected after intercourse. Furthermore, women
seem to time their orgasms with their affair partners to coincide more closely
with when they ovulate. These findings, together with the theory of sperm
competition, may solve the puzzle of why women place such importance on sexual
gratification as a benefit from extramarital liaisons.

In the modern world, with many women taking contraceptives, the
connection between sexual orgasms and actual reproduction may be severed. But
women’s sexual psychology, forged over millions of years in an ancestral world
devoid of the pill, continues to get played out in the modern world. The
importance to women of sexual gratification, and orgasms in particular, may be
a key motive driving women to act on their unfaithful passions.

It’s possible, of course, that this theory is wrong. Don Symons
argues that female orgasm lacks an adaptive function. He draws an analogy to
men’s nipples, which have no function, but are merely incidental byproducts of
the common design men share with women early in development. Women’s nipples
and men’s orgasm have clear functions: to breastfeed a baby and to ejaculate
sperm into the woman’s reproductive tract, respectively. But women’s orgasm,
like men’s nipples, have no evolutionary purpose, Symons suggests. He may be
right. But the weight of the evidence from several labs around the world is
weighing in against the interpretation that women’s organism is a byproduct.

Women I’ve talked to tend to have strong opinions on the topic.
When I recently gave a lecture on these findings at the London School of
Economics, a woman afterward gave me a cartoon that beautifully illustrated
this point. Two peahens are staring at a peacock, who is striving valiantly to
display his plumage to them with a maximum of flourish. One of the peahens
tries to stop him with this quip: “Cut the crap and show us your willy!”

Whether women’s orgasm proves to have a function, as seems
likely, or whether Symons turns out to be right, the competing theories have
had the healthy effect of stimulating more research on this neglected side of
women’s sexuality.

Generalizations about “women” are always problematic for one
fundamental reason—not all women are alike. General trends are important, but
we must also consider the variability within each sex. Some women delight in affairs,
gaining self-esteem and a bounty of other benefits. Other women express horror
at the mere thought of breaking marital vows. Women have a varied menu of
sexual strategies at their disposal. The strategic combinations they select
depend on individual circumstances.

Do women who pursue a strategy of extrapair mating have a
different cost-benefit evaluation system than monogamous women? Is their
behavior driven by the perception that more profound benefits will flow from
casual flings? If so, precisely which benefits do these women perceive to be
forthcoming?

To answer these questions, Heidi Greiling and I contrasted women
who were actively pursuing a short-term sexual strategy with those who remained
monogamous. They differed substantially in their perceptions of benefits. The
short-term strategists perceived two key benefits as more likely to be reaped:
receiving sexual gratification from an affair partner and elevating their
self-esteem because more than one man found them sexually attractive.

The greatest differences between the two groups, however,
centered not on how likely these benefits were to be received, but rather on
how beneficial they would be when they were received. Women who are short-term
sexual strategists perceive the direct sexual rewards to be far more beneficial
than do women adopting a monogamous strategy—rewards such as engaging in sexual
experimentation, experiencing more sexual orgasms, getting pleasurable sexual
stimulation aside from orgasms, and receiving oral sex from the affair partner
that her regular partner was unwilling to provide. Sexual benefits seem more
important for women who persue a multiple-mate strategy.

Other rewards centered on the acquisition of resources:
receiving expensive designer clothing, becoming friends with high-status
others, discovering other attractive partners through the affair partner, and
advancing a career. The more promiscuous women appear to capitalize on their
sexuality by using multiple partners to gain status, material goods, and access
to a wider pool of potential mates. These women have the sex appeal to secure
such benefits.

The final cluster of rewards involves the cultivation of new
skills and abilities: improving techniques of attraction, for example, and
being better able to seduce a man because of experience gained through an
affair partner. Some women see affairs as vehicles for honing their mating
skills to become more successful at implementing a short-term mating strategy
or to attract a more desirable permanent partner.

Why do some women pursue a monogamous mating strategy while
others opt for a strategy of multiple partners? One possibility is that casual
strategists possess more abundant sexual assets that allow them to be more
successful in garnering the various benefits from a short-term strategy. A
woman with less sex appeal may be more limited in her successes in this domain.
According to this explanation, casual strategists should be viewed as more
“sexy” than monogamous women, although not necessarily more “attractive.” Although
sexiness and attractiveness are correlated, some women are more sexy than
attractive, whereas others are more attractive than sexy. The actress Ellen
Barkin, for example, might be judged highly sexy, but not necessarily at the
top in pure beauty. Meryl Streep, in contrast, might be judged to be highly
attractive, but not necessarily at the top in raw sex appeal. If the “ability
to successfully implement the strategy” explanation is correct, then Ellen
Barkin would be more able to thrive in short-term pursuits, whereas Meryl
Streep would be more successful going for monogamy.