The Dangerous Passion: Why Jealousy Is as Necessary as Love and Sex (25 page)

A more subtle predictor of infidelity involves the qualities of
the spouse of the cheater. Do spouses with certain personality characteristics
make married life sufficiently miserable that their partners seek love from
others? To answer this question, Shackelford and I examined each of the
personality characteristics of husbands and wives, and correlated them not with
their own susceptibility to infidelity, but rather with their partner’s
susceptibility to infidelity. Two personality characteristics emerged as
significant predictors: emotional instability and quarrelsomeness.

Emotional instability is a broad personality characteristic
marked by large mood swings. During the normal stresses and strains of everyday
life, emotionally unstable people tend to get thrown out of whack more easily
than their more stable peers. Furthermore, they have a longer latency in
returning to baseline, remaining upset for a longer duration after the
distressing event. Good behavioral markers of emotional instability include
obsessing over something they can do nothing about, putting themselves down
repeatedly and without good reason, and agreeing to things without
understanding why and without taking a stand of their own. On the positive
side, emotionally unstable persons are more emotionally responsive than others,
and this quality is sometimes linked with creativity. On the other hand, highly
unstable individuals can turn a loving marriage into a living hell, and
sometimes drive a partner to seek solace in the embrace of another.

When emotional instability is linked with another personality
characteristic—quarrelsomeness—marriages turn into cauldrons of conflict.
Precisely how this works was revealed in our long-term study of married
couples. Quarrelsome spouses are condescending toward their partners, insist
that their own opinions are superior to their partner’s opinions, and call
their partner stupid. They neglect and reject their partner, laying the
groundwork for the partner’s needs to go unmet. They tend to abuse their
partners emotionally, call their partners nasty names, and demean them in front
of others. The combination of emotional instability with quarrelsomeness proves
disastrous for the quality of the marriage, increases the probability of
divorce, and can drive a spouse into another’s arms.

The spouses of emotionally unstable and quarrelsome individuals
are more likely to flirt, passionately kiss, and romantically date others.
These spouses are also more likely to cross the sexual line and have
intercourse with others, either for a single night or for a more enduring
extramarital affair. It is as though affair partners provide a safe haven from
the nightmare of their marriage, a refuge where they are appreciated rather
than abused. It is not inevitable that quarrelsome and emotionally unstable
individuals drive their spouses to seek gratification elsewhere, but these
qualities raise the odds.

The unfaithful rarely broadcast their betrayals. On the
contrary, they take great pains to conceal all clues, meet in out-of-the-way
places, mask telltale sexual scents, create alibis for unexplained absences,
get close friends to cover for them, and generally try to act as if everything
is normal. Concealment creates a co-evolutionary arms race between deception
and detection of deception. Because the costs of discovery can be catastrophic,
the unfaithful have become more and more skilled at evading detection. Because
the costs to the betrayed are so severe, however, selection favors those who
penetrate the mask of deception. In short, the co-evolutionary arms race has
created exquisite sensitivity to the most subtle signals of betrayal, while
simultaneously creating extraordinarily skilled evaders of detection.

In 1997, Todd Shackelford and I explored an array of cues to
infidelity. As a first step, we asked 204 men and women to list clues that they
believed would evoke suspicions of sexual or emotional infidelity, separately.
On one form, labeled “Cues to a Partner’s Sexual Unfaithfulness,” we asked
people to think of a past, current, or future romantic relationship, and then
asked them: “What cues would lead you to suspect that your partner is sexually
unfaithful to you?” On a separate form, labeled “Cues to a Partner Falling in
Love with Someone Else,” we asked: “What cues would lead you to suspect that
your partner is falling in love with someone else?” We ended up with 170 cues,
which provided the raw information for the subsequent study.

Our next study determined which cues were most diagnostic of
sexual and emotional infidelity, and furthermore determined which cues were
differentially
diagnostic
of the two types of infidelity. That is, which cues are more
likely to signal a sexual betrayal rather than an emotional betrayal and vice
versa?

The most diagnostic signal of
sexual infidelity
was
rather obvious: actually discovering a partner in bed with someone else. Other
signals were subtle. Physical signs include detecting the odor of sex or other
unfamiliar scents, such as perfume, on the spouse. Another important signal
involves abrupt or unexpected changes in the sexual interest of the spouse. A
partner might suddenly have difficulty becoming sexually aroused, for example,
or become more mechanical and bored when having sex. Rapid increases in sexual
interest can also signal sexual infidelity—acting more interested in sex than
usual, talking about sex more, or suddenly trying out new sexual positions.

Changes from the normal routines of everyday life can trigger
alarm bells. Suddenly buying new clothes or changing clothing styles, for
example, can signal a sexual infidelity. One woman, married to a dentist she
found dull, started having an affair with an exciting and successful professor.
She suddenly started wearing more tight-fitting clothing, had her belly button
pierced, and walked with more flair and confidence. Eventually, after her
husband discovered the affair and she broke it off with the professor, she
returned to her previous duller style of clothing, had her navel ring removed,
and appeared more demure in demeanor.

Other changes can also set off alarm bells—changes in food
preferences, musical tastes, or even choice of books. The clinical literature
brims with cases of the Othello syndrome inspired by a partner coming home with
a trendy new shirt, developing a sudden interest in hip-hop or jazz, or
becoming an avid reader of Updike or Nabokov.

We discovered that other signals are more diagnostic of
emotional
infidelity
. The most obvious involved actual discussions of dissolution.
The partner might start talking about the end of the marriage, for example,
declaring that the love has gone out of the marriage, or might even suggest
they begin seeing other people. A more subtle cue is emotional disengagement,
such as failing to respond to a spouse’s declaration of love. Ceasing to say “I
love you” proved to be one of the most diagnostic cues of emotional infidelity.
Forgetting their wedding anniversary, the spouse’s birthday, and other special
dates, as well as not sharing personal feelings with the partner are all
manifestations of emotional disengagement. Displays of guilt proved more
diagnostic of emotional than sexual infidelity: failing to look the partner in
the eyes, being unusually apologetic toward the partner, and acting guilty
after having sex with the partner.

Showing either a reluctance to discuss a specific person or an
increased reference to a specific other person stand out as signals of
emotional infidelity. Avoiding talking about another person or acting nervous
when that person’s name crops up in conversation revealed the reluctance side;
beginning to mention another’s name more frequently reveals the increased
reference side. Perhaps most devastating, accidentally calling one’s spouse by
another person’s name proved to be an especially strong signal, not to be
recommended under any circumstances, but especially not when in bed with one’s
spouse! One woman I interviewed said that she made a point of calling both her
husband and her lover “sweetheart” to avoid the possibility of slipping up in
this manner.

Another potent cue to emotional infidelity involves becoming
increasingly angry, critical, or inconsiderate of one’s spouse. Looking for
reasons to start arguments with one’s partner, failing to consider the
partner’s needs, acting rude and abrupt, finding fault with trivial things, and
becoming less gentle during sex also signal emotional detachment. The final
sign is an increased apathy toward the partner. A spouse might get less excited
than usual, less often invite the partner to spend time with him or her, fail
to invite the partner to attend social events, and generally act bored.

An interesting pattern of sex differences surfaced in judgments
of how diagnostic each cue was of infidelity. First, women are more likely than
men to judge a wide array of clues as symptomatic of emotional infidelity:
sexual disinterest, a partner’s guilt and apathy, displays of anger and criticality,
and emotional disengagement. It’s important to stress that men are not
oblivious to these signals. Rather, women seem more finely attuned to the
subtle emotional changes in their husbands that might betray a change in
emotional commitment.

The second sex difference pertains to a sensitivity to signals
coming from the opposite sex. In our study, both men and women evaluated each
cue when it was discovered in either a man or a woman. Women judged exactly the
same cues—for example, emotional disengagement—to be more typical of men’s
infidelity than women’s infidelity. Similarly, men judged cues such as
emotional disengagement to be more characteristic of infidelity in women than
in men. Women appear to be more sensitive to men’s defections, and men to women’s
defections, which makes good adaptive sense. After all, the most severe
adaptive threat comes from the infidelity of one’s partner, not from the
infidelity of members of one’s own sex, except when same-sex friends lure one’s
partner into an affair—a double deception.

Aside from death, nothing is inevitable or assured, not good
health, not lifelong love, and certainly not the fidelity of one’s partner.
Cues to infidelity get intentionally muted and muffled. Human minds have
evolved to be extraordinarily sensitive to these inconspicuous whisperings. Our
psychology of infidelity detection amplifies these signals because they pose an
adaptive threat. We are sometimes wrong. Emotional disengagement might indicate
a stressful day at the office rather than a passionate involvement with
another. But those in our evolutionary past who ignored subtle signals of
betrayal suffered reproductively relative to those who detected them.

Worldwide, infidelity is the leading cause of divorce. In
studies of Western cultures, as many as half of all divorcees cite a spouse’s
sexual infidelity as one of the primary reasons for the divorce. One woman put
it this way: “I tried to forgive him, but every time we made love, the image of
his lover invaded my mind. I saw her in my husband’s arms, him embracing her,
whispering into her ear. I could not shake these images, and so I had to end
it.” Not all couples, however, divorce following an infidelity. Some manage to
stay together, patch things up, muddle through the bad part, and emerge from
the violation to a new beginning. What distinguishes couples who stay together
following an infidelity from those who break up?

As part of the study of 107 married couples, Shackelford and I
asked each husband and wife, in private and separated from the glare of their
partner’s eyes, whether they would seek a divorce if their spouse engaged in
intimacies with another. Husbands and wives, on average, showed strikingly
similar estimates. In response to a partner flirting with someone else, only 4
percent of the husbands and 3 percent of the wives declared that they would
seek divorce. This jumped to 20 percent and 21 percent for a partner
passionately kissing someone else, and 36 percent and 37 percent for a partner
going out on a romantic date with someone else. Responses to the more serious
forms of sexual infidelity resulted in larger percentages. For both sexes, 49
percent declared that a partner’s one-night stand would trigger a divorce, and
56 percent indicated that a partner’s brief affair would trigger a divorce. The
greatest estimates of divorce were reserved for a partner who had a serious
affair. Fully 67 percent of the husbands and 69 percent of the wives avowed
that this greatest of all violations would produce an irreparable breach. The
most remarkable finding from this study is not that the severity of the
infidelity raises the odds of divorce; rather, it’s that nearly a third of the
sample professed that they would
not
seek divorce, even after their
partner had a serious affair with a rival. Who are these forgiving souls?

The relative mate value of the partners proved crucial, but
primarily from the woman’s perspective. Recall that male and female
interviewers evaluated the physical attractiveness of each person and their
“overall attractiveness as a potential mate (market value to opposite sex).”
Wives judged as more physically attractive than their husbands stated that they
would be more likely to divorce unfaithful husbands. Similarly, wives higher in
mate value than their husbands declared that they would break from unfaithful
husbands. Women who were
lower
than their husbands on attractiveness
and mate value, in contrast, were more forgiving. These women indicated that
they would probably remain with their husbands, even if these men had a
one-night stand or a brief affair. It’s as though these women thought: “I’m
really lucky to be with him, and would have enormous difficulty replacing him
with someone as desirable, so I’ll stick it out.”