The cool thing about fantasy relationships is they don’t require any work.” Therapy is similar for online or traditional affairs, with couples working on issues of trust, betrayal and forgiveness.

“It’s really difficult to track what your partner is doing,” Hertlein says.

“There aren’t receipts for hotels or dinners or excursions.” With the faceless nature of the Internet, anonymity also is easy to come by.

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.

“The Internet is opening up these new ways of exploring your sexuality and that includes infidelity,” she says.

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.

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.

With the burgeoning use of the Internet, many practitioners are seeing more couples because of online affairs and are addressing new issues in therapy, psychologists say.