Young sees more women who are online cheaters, in part, she says, because women gravitate toward erotic chats and webcam sessions while men often are drawn to pornography.

Several studies have focused on the “AAA engine” that drives online affairs, namely accessibility, affordability and anonymity.

“The Internet is extremely accessible no matter where you are,” Hertlein says.

“Your primary partner will never be able to compare with the fantasy partner,” Hertlein says.

“They will never win.” According to Young, people with low self-esteem, a distorted body image, an untreated sexual dysfunction or a prior sexual addiction are more at risk to develop addictions to cybersex or online pornography.

Every time you walk by, you’re asking yourself if he or she is using it for an affair.” While most relationships are hampered by such workday realities as household chores and paying the bills, online relationships exist in an electronic nether world where strangers can construct their own identities, Hertlein says.

“On the Internet, you can be whoever you want to be. You don’t have to be this constrained person you think you should be.” Fantasy also is a huge factor in online affairs, and fantasy always trumps reality.

Women usually feel more threatened by the emotional betrayal of a partner’s online affair, while men are more concerned about physical encounters, Hertlein says, but the gender differences are lessening.

“That is starting to even out in part because of the equality of opportunity that the Internet brings to everybody,” she says.

“Women are supposed to be the nurturers and the matriarchs in our society.” Due to the secretive nature of online affairs, reliable statistics are hard to find, but a 2005 study of 1,828 Web users in Sweden offers evidence about the prevalence of cybersex and online affairs. A 2008 Australian study offers more insight into Internet affairs. More than half of the respondents believed an online relationship constituted unfaithfulness, with the numbers climbing to 71 percent for cybersex and 82 percent for in-person meetings.

Almost a third of the participants reported cybersexual experiences, and people in committed relationships were just as likely to engage in cybersex as those who were single. While men’s interest in cybersex decreased with age, women’s interest increased slightly, with 37 percent of women age 35 to 49 reporting cybersexual experiences compared with only a quarter of men in the same age group (, Vol. It found that of 183 adults who were currently or recently in a relationship, more than 10 percent had formed intimate online relationships, 8 percent had experienced cybersex and 6 percent had met their Internet partners in person (, Vol. Kimberly Young, Ph D, who directs the Center for Internet Addiction Recovery in Bradford, Pa., says about half of the couples in her practice are seeking counseling because of online affairs or excessive use of online pornography.

While men traditionally have been the more unfaithful sex, gender roles are reversing in some cases as more women experience cybersex.