By Diana Rodriguez; Medically reviewed by Lindsey Marcellin, MD, MPH

When it comes to infidelity, there are a number of myths and misconceptions. First of all, infidelity isn't limited to sex or physical contact. And second, men aren't the only ones who cheat.

Women also seek comfort and satisfaction (in and out of the bedroom) outside of their marriages, and almost as frequently as men do, says Sarah Cook Ruggera, MFT, a marriage and family therapist in San Diego. It's estimated that the number of men who cheat on their wives is up to 60 per cent. But as many as 55 per cent of women also cheat, says Ruggera, a number that's climbing and today is likely on a par with men's statistics.

It's also important to clarify that you don't have to have sex to commit infidelity. Infidelity can be "some kind of inappropriate intimacy outside their relationship, be it emotional or physical," explains Ruggera. "Most affairs are not always about sex."

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SEE: Why do women cheat? For these reasons -- story continues below:

• Because It's Easier To Do So
• To Get Out Of A Bad Relationship
• To Find That Spark
• An Unsatisfying Sex Life
• Revenge And Retaliation
• Trouble Within
• For The Same Reasons As Men

Cyber-Cheating

For instance, cyber affairs are allowing computers to invade the bedroom in more ways than one. “Cheating” can occur online, without ever having sex or even seeing the other person, but it's certainly an act of unfaithfulness. A recent study found that while a man didn't consider an online affair to be cheating because there was no physical contact, his wife disagreed. During the course of therapy to help repair the marriage, other problems gnawing away at the couple before the online affair surfaced, such as a lack of communication, being unhappy with their sex life, and simply feeling bored. But the study also indicated that people may cheat (at least online) without those marital problems.

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Something Is Missing

Why are so many men and women willing to break their marriage vows? Some women who cheat have some type of mental illness or personality disorder. But primarily why women cheat is because there is an emotional disconnect or feeling of neglect, says Ruggera. "In many cases of infidelity, it is about feeling emotionally connected to someone."

Women and men cheat because they're simply missing something in their relationship. When women start to feel disconnected and distant, loneliness and depression can set in. Eventually, they may look outside their relationship for someone who can meet their emotional and physical needs and ease their loneliness.

What Issues Look Like

Relationship problems may trigger infidelity and explain why women cheat. The reasons may include:

• To get out of a bad relationship. Women who cheat may want to escape their relationship, and not know how to do it. Sometimes it's too hard to say you want out, so women cheat instead. Infidelity "is a way of sabotaging the relationship because for whatever reason the woman is already unhappy, dissatisfied, disgruntled, and wants out," says Ruggera.
• To find that spark. With money worries, exhaustion, bills, and kids, the spark that kept a relationship hot at first can often fizzle out. "Romance can get lost in the day-to-day routine of life," says Ruggera. Even if they're not on the hunt for an affair, some women may become seduced by the temptation of the “high” that comes with any new relationship.
• An unsatisfying sex life. If the sex isn't satisfying and a woman isn't feeling emotionally fulfilled in her relationship, "her interest may wander toward other men," says Ruggera. A woman can also start to feel like she's unattractive or her partner doesn't desire her if their sex life is slow.
• Revenge and retaliation. If a husband has cheated, sometimes a woman may cheat to get back at him. It's an effort to get the husband to feel "the hurt, anger, and jealousy that she felt," says Ruggera.

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Problems Within

Low self-esteem can be another reason why women cheat. "Gaining attention from men can boost their self-confidence and self-esteem," says Ruggera. "Compliments, phone calls, flowers, and notes from another man are flattering and make a woman feel more attractive and wanted."

Another reason why women — and men — cheat is that they do what they know. If they saw infidelity in their parents' relationship, both men and women may follow those patterns in their own lives.

Women vs. Men

Women who cheat do so for many of the same reasons that men do -- attraction issues, unsatisfying sex life, unhappy relationship, feelings of neglect, looking for an ego boost, and a disconnect in the marriage.

"Women are not that different from men when it comes to cheating, except that they are more apt to fall in love with their new partner," says Ruggera. The reason is hormonal -- oxytocin, a hormone, stimulates the brain to give a woman that rush from being in love.

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Perhaps because of that, women are also more likely to care about the emotional aspects of infidelity when their partners cheat. In a recent study published in the journal Personality and Individual Differences, female victims of cheating asked about sex in just 29 per cent of cases but about love in 71 per cent of cases, compared with 57 per cent and 43 per cent of cases, respectively, for men.

Working on Intimacy

If you want to protect your relationship from the temptation (and destruction) of infidelity, know that it needs to be nurtured and cared for — water it, feed it, give it love and sunlight to watch it grow and blossom.

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"The most effective way to keep a relationship or marriage healthy is to work on it every day and evaluate it on a regular basis," suggests Ruggera, adding that if a couple makes a concentrated effort to make a relationship a priority, enjoy time together, and work on clear communication, they can avoid feeling like they need someone else to make them happy.