Physical infidelity — or sexual interaction with someone outside your relationship — is the most obvious type of cheating. Though statistics vary widely, most show infidelity at a rate below 25% of individuals, like one study done of heterosexual couples through the Indiana University Center for Sexual Health Promotion that was published in Archives of Sexual Behavior. But women tend to define more physical behaviors as infidelity than males, according to Texas State University researchers Victoria Thornton and Alexander Nagurney in a 2011 study of 125 male and 233 female college students titled “What Is Infidelity?” in Psychological Research and Behavior Management. Women also tend to see emotional connections to others as cheating where men may not consider them to be.This suggests that how you see handholding or a kiss on the cheek might depend on your gender, so be clear with your partner to avoid later issues.

Online infidelity, or cyber cheating, is just as traumatic to relationships as physical cheating, notes psychologist Brendan Smith in “Are Internet Affairs Different?” on the American Psychological Association website. Smith also notes that although men have traditionally been the more unfaithful sex, the rates for women are now climbing because of the emotional nature of online relationships. Cyber cheating may involve online flirting, photo sharing, or even mutual masturbation via video chat or instant messaging. Despite the lack of physical touch, these attachments can get very real, very fast. Partners who discover that their significant other has been cyber cheating are just as hurt, just as angry, and likely to sever the relationship.

Emotional infidelity — having a close emotional attachment to another, or falling in love with a platonic friend — can be damaging. But not all close friendships are dangerous, as only certain factors lead to actual cheating, notes College of Staten Island researcher Karen Wilson et al. in a review of research titled “The Gray Area” in the Journal of Social Psychology. Though some identify close friendships as emotional cheating, researchers found that ambiguous behaviors — such as talking or sharing personal information — were more related to friendships and that these individuals avoided sexual situations. However, they also found that explicit and deceptive tactics -- such as lying to one’s partner or engaging in flirting behaviors -- led to more guilt and more acting on those attractions toward friends. If you feel guilty or find yourself thinking about a friend in a sexual way, you may be engaged in emotional cheating.

Women may be catching up in the cheating department. The increase in female infidelity may be based on opportunity, the validation of attractiveness, emotional connection or the sexual thrill of a new relationship, says research psychologist Peggy Drexler in a Huffington Post article titled, "The New Face of Infidelity." Women may also be more susceptible to emotional connections online that lead to later physical affairs. And, contrary to popular belief, men also cheat for emotional connection according to marriage counselor M. Gary Neuman in a WebMD article, "The Truth About Why Men Cheat." They also tend to get to know the woman for months beforehand, as opposed to just jumping into bed. Regardless of gender, emotional connection is a critical relationship component to avoid cheating.