Watching pornography, masturbating and now becoming involved in virtual relationships are all activities that take a person's attention away from their primary relationship, one marriage expert told ABC News, but whether it's cheating depends on the degree to which someone does it.
"The same rules apply to this as say, pornography," said psychoanalyst Bethany Marshall. "It's the amount of energy that is devoted to the excitement away from the relationship."
"Some of the ways to determine if it's cheating is if you're investing more energy and excitement outside your relationship rather than in it and if your partners would disapprove and you're knowingly going behind their back," said Marshall. "It's a perversion if you're more in your fantasy life than your real one."
"Character fantasies are worse than porn because you're actually developing an attachment with another character, and if you keep returning to this person again and again then it's an ongoing relationship."
Opinions about cheating in real versus online worlds abound and there's no consensus on what's right or wrong.
"Nobody is really sure how people perceive online relationships or when they are cheating," said Nick Lee, a recent doctoral graduate from Stanford who studies the psychologies of virtual environments like Second Life. "It's not clear to what extent chatting someone up online is a date or if it's OK if you have a real relationship."
"If you're role-playing relationship online and you don't want your spouse to find out, then there's probably something wrong," said Lee. "If you feel like it's something you want to hide, then that's a good litmus test."
Lee chalks up the popularity of relationships in virtual worlds to the feeling of invisibility a user enjoys knowing that his or her identity is unknown.
"Users say they feel like they really get to know the person by getting to know them in a virtual environment," said Lee. "In the physical world, if you have access to great makeup and stylish clothes [that] has a lot to do with how much money you have and what your social status is. The thing in Second Life is that you can buy that body with a click of the button."
Relationship experts say online worlds can be a good release for many people, but it's wise to set boundaries in programs like Second Life.
"In good mental health, you want the fantasy — whatever the fantasy is — to actually point you in a real relationship with a real person," Marshall told ABC News.
Cheating in the virtual world though is likely to continue to be a problem area for real-life relationships, said Marshall.
"More relationships are breaking apart because of [Internet] access," said Marshall. "People are going to have to interact and really be honest with their partners."