1. Dissatisfaction in Relationship

This can be seen as the underlying theme of the majority of motivations for infidelity. Dissatisfaction, explains Skurtu, is where it starts. "People justify this by saying, 'We are in a bad patch.'" she continues. "Then the opportunity arises for one person, and instead of stopping things before they start, they justify crossing a boundary, with, 'My partner doesn't care anyway. It's completely innocent.'"

For every relationship boundary crossed, the person has to justify their behavior to themselves first, then they are able to compartmentalize the actions. Not finding satisfaction in a current relationship can trigger someone to seek that satisfaction elsewhere or even use the act of cheating (whether consciously or unconsciously) as a catalyst to end their current relationship.

2. Low Self-Esteem

When a woman is struggling with low self-worth, it may spur them to look to external sources for the attention and validation that they and their partner are unable to create and sustain. "Low self-esteem starts out looking like, 'Why would anyone find me attractive?' Then when someone starts to show that attention, it feels really good," says Skurtu.

A woman who cheats may rely on affairs to provide them with proof of their value or desirability. When one fling ends, it may cause them to feel neglected or worthless, so they pursue a new romantic interest—and the cycle continues.

3. Emotional Starvation

While studies suggest that men who cheat are primarily motivated by sex, women who cheat tend to do so to fill an emotional need.3 And in the case of an emotional affair, sex isn't part of the equation at all. Whether the affair is physical or emotional in nature, a woman may cheat because they crave conversation, empathy, respect, devotion, adoration, support, or some other connection that's lacking in their current relationship.

"Some people convince themselves emotional is not a real affair. However, most sexual ones start emotional," says Skurtu "I find it pretty rare to have an only sexual affair without some emotions because they usually start as friends. That's how you start crossing boundaries and justify the behavior."

4. Anger or Retribution

Some women enter into a relationship with an idealized image of how their spouse should behave. When the partner falls short of expectations and can't meet their every need and desire, it can create a divide in the relationship that provides the impetus to stray.

Some women may resent their partner for another reason, such as a partner's past affair, and use their own infidelity as retaliation.

5. Lack of Excitement

You've likely heard of the term serial cheaters—people who cheat for the thrill of it. They may love their significant other but yearn for those endorphin-fueled interactions that make a new relationship so exciting.

"I think as a society we don't honestly address how boring work and family life can be at times," explains Skurtu. "I was recently watching the show Good Girls, and they turn to street crimes. It's addressing the same thing: boredom. I feel people are more likely to cheat than to get involved in crimes, but it's the same premise."

In fact, a study at the affair dating website AshleyMadison.com found that 67 percent of heterosexual, married women who cheat sought out "romantic passion," yet 100 percent of the women denied any intention of leaving their husbands; some even "stated their overt love for their husbands, painting them in a positive light."4

6. Sexual Deprivation

Try as we might to keep the spark alive, the excitement that accompanies a new relationship only lasts so long. Predictability and familiarity will eventually overtake the quality and frequency of sex. It's not surprising, then, that some women who cheat are missing those thrilling hallmarks of a relationship's beginning stages, when passion and intrigue have yet to give way to routine. In fact, Skurtu believes this is historically one of the motivators behind male-centric infidelity: "It might have been an expectation that at a certain point, sex was not a big part of marriage so cheating was a necessary evil."

7. Loneliness

A woman who cheats may have a partner who works long hours, leaving them home with the kids all day. Perhaps they've found themselves in a stage in life when it's harder to make friends or maybe their significant other is contending with a chronic illness. Whatever the reason, loneliness or feelings of isolation and disengagement can "provide the perfect ingredients for an affair," says Skurtu. "They feel lonely and someone else starts meeting the unmet needs."

8. Insecure Attachment Style

Attachment theory suggests that early childhood relationships influence how we perceive and behave in our intimate relationships as adults. Depending on the care and nurturing (or lack thereof) that one receives as a child, they'll fall into one of three attachment styles as adults: secure (having well-adjusted expectations and approaches to relationships), anxious (exhibiting fear of abandonment), or avoidant (preferring to retain their independence from others).5

People who identify with anxious and avoidant attachment styles are more likely to display characteristics that interfere with a healthy romantic relationship (think clinginess and dismissiveness).5 Moreover, they're more likely to cheat, as they seek out reassurance from a third-party partner or attempt to avoid the intimacy of the primary relationship.6 "There's always a sense of 'what's on the other side' and never fully being happy or secure in oneself," explains Skurtu. "This type of person may struggle to be happy in any relationship."

9. Midlife Crisis

While midlife crises generally affect people between the ages of 35 and 60, the event has less to do with age than extenuating circumstances. Major life events, such as the death of a parent or a milestone birthday, may trigger a midlife crisis in a woman, causing them to wrestle with the burden of greatness; that is, the sociocultural expectation that women can and should "have it all"—a successful career, a loving partner, adoring children, and so on.

"People think, 'I only have so much time left. What am I doing with my life?'" says Skurtu. A woman may act out of character as she attempts to realize her potential and make up for lost time.

10. An Underlying Condition

According to Block, depression and infidelity go hand in hand. "[An affair is] exciting, so much so that the brain can begin to pump out dopamine, norepinephrine, and serotonin—neurotransmitters we produce when we’re attracted to someone, but which, not so coincidentally, are the same chemicals produced when we take antidepressants," he says. In other words, a woman who cheats could be self-medicating through their infidelity, even if they don't realize the true reason behind their pleasure.

11. Opportunity

Few acts of infidelity are premeditated, asserts Skurtu, but rather a result of an unexpected opportunity. "They feel down and another person in a similar boat crosses their path. They start commiserating and then it moves on from there," she adds. People in this situation usually can't explain the reason behind their infidelity. "It sort of just happens, even though, really, there are specific moments of truth that can make or break the potential affair."

Similar opportunities exist in the digital realm, too. Social media, dating apps, and texting have revolutionized the ease at which we can connect with others, sometimes serving as a springboard for affairs—even if the interactions start innocently.

12. Numbing Difficult Feelings

People can develop a wide variety of coping mechanisms to deal with difficult emotions, sometimes choosing strategies that have emotionally numbing effects as an easier option than facing them. Sex, drugs, alcohol, and other addictions or compulsive behaviors are just a few examples.

"An affair is an escape from reality," says Skurtu. "[When] women struggle to be honest about what they want with their partners and instead seek out a fantasy world that not only numbs but creates an amazing jolt to the system, there's an adrenaline rush to cheating."