From the comfort of their homes and with just a few clicks of a mouse, virtual universe residents can do just about anything they want.
Second Life, an online world that lets users navigate through a digital planet, has a functioning economy with its own currency, an array of employment opportunities and a bustling social scene, nightclubs included.
And, for those looking for virtual intimacy, residents of Second Life can connect with other users, known as "avatars."
The universe, which has a population of more than 8 million, has seen approximately 35,796 of its residents engage in partnerships, according to Linden Lab, the developer of Second Life. Partnerships are akin to marriage and participants indicate these on avatar user profiles.
Sometimes these online unions, marked by instant message communication and even virtual sex, lead to real-life phone talk, meetings and all the activities that may ensue from that.
For Heart, a 37-year-old woman on Second Life who asked to use her avatar's name, a relationship that began in the virtual world is now part of her real life. Her two-year online relationship led to in-person meetings and eventually a real-world partnership.
Second Life led to troubles in the relationship with her boyfriend at the time, Heart told ABC News. Heart said she eventually left her boyfriend for her Second Life partner.
"[Joe] filled all the gaps that were missing in my real-life relationships," said Heart. "My real-life boyfriend used to walk past the screen and see what was happening and I used to tell him it was no big deal and it was just a game. I felt guilty about it."
While Heart said that she and Joe had sex in Second Life, she said they found it more entertaining than sexually stimulating.
Even those who never meet their Second Life mates may encounter difficulties with their flesh-and-blood partners.
Last week, The Wall Street Journal published a story about Ric Hoogestraat, a Phoenix man whose wife, Sue, is growing tired of his continued interested in Second Life. Much to Sue's dismay, Hoogestraat's avatar had gone as far as marrying another avatar on Second Life.
It's "devastating" when her husband is too busy having sex in the virtual world to pay attention to her in the real one, Sue told the newspaper.
Couples similar to Heart and Joe are redefining the bounds of dating, marriage and infidelity.
For those relationship experts trying to make sense of it all, there's a growing debate over what constitutes cheating, online and off.
Technically speaking, any energy — emotional, physical or monetary — exerted outside of a person's primary relationship can be considered cheating, relationship experts told ABC News.
"Whether it's an emotional affair with no sexual contact, an e-mail relationship or a virtual-reality relationship, they're all different forms of the same phenomenon, which is channeling to someone outside of the relationship," said Susan Heitler, a clinical psychologist and author of "The Power of Two: Secrets to a Strong and Loving Marriage."
"It's cheating in the sense that it's forming relationships and fostering loving feelings or sexual feelings toward someone or something outside the appropriate partner," she said.
Virtual cheating may have the same sting as real-life cheating, too.
"The impact that they all have is that they are detracting from the primary relationship," said Heitler.