Katy Guest: The fall-out when two worlds collide

You know how it goes: boy meets girl; boy falls in love with girl; boy and girl get married; girl catches boy having sex with a prostitute and a series of digitally-enhanced women; boy and girl end up divorcing – that's both their online characters in an internet-based game world, and in real life. So it goes in Cornwall, where Amy Taylor and David Pollard (left), who met on the virtual reality game Second Life, are divorcing on the grounds of his, um, second life.

Ms Taylor, whose online marriage was dissolved in May, said: "He never did anything in real life, but I had my suspicions about what he was doing in Second Life." Mr Pollard said: "Amy never did anything around the house. She just played World of Warcraft all the time." Here are other ways it can go wrong when two worlds collide:

In January, the BBC2 documentary, Wonderland: Virtual Adultery and Cyberspace Love, found Carolyn, an American mother of four who flew to London to meet a man she had fallen in love with on Second Life. Her real husband was not thrilled: "They're not going to go there and crochet together." Unfortunately for Carolyn, by the time she got to England, Elliott (skinnier and nerdier than his online avatar) didn't even want to crochet.

In Japan, a woman is awaiting trial for the online-only murder of an imaginary man who divorced her. The piano teacher from the island of Kyushu logged on to the cad's account and "killed" his avatar when he dropped her for a younger, hotter avatar whom he had subsequently met in the online world of MapleStory. The woman is being investigated on suspicion of illegally accessing a computer and manipulating data.

Such is the greater appeal of engaging in mortal combat with a legion of orks than conversation with a real-life partner that self-help groups have been set up for gaming widows. One said of her husband: "When Paul's not playing World of Warcraft, he's restless and dissatisfied and desperate to escape to this weird fantasy world." The pair are still married. In theory.

In August, a 33-year-old woman was arrested for attempting to kidnap her online ex-boyfriend. Kimberly from Durham, North Carolina, was found in the home of her 52-year-old former paramour, having travelled to Delaware to find him and bound up his dog with duct tape. Her husband, Michael, said: "I always knew that she could be obsessive ... ."

On 15 September 2006 17-year-old Tommy from upstate New York shot his co-worker Brian for stealing his girlfriend, Jessi, or TalHotBlondbig50, whom he had met on the social-networking site Pogo. Except that Tommy was not real, and nor was his "father", Tom Snr; both were the fictional creations of a 45-year-old, married factory worker. And Jessi's role had been entirely performed by her mum, Mary. The only person in the scenario who was playing himself all along was 22-year-old Barrett, a student at Buffalo State College. He died of his injuries.

Not all online worlds result in craziness. In Spain, health authorities launched a virtual GP's surgery so teenagers can talk openly about sexually transmitted diseases. A Second Life group called Obama for President organised a virtual music festival to raise real-world funds. And in his 2007 book, Second Lives: A Journey Through Virtual Worlds, Tim Guest hung out with a group of people with disabilities near Boston. They have constructed an avatar called Wilde Cunningham, who is either a male punk or a feisty woman. Online they can walk, dance, sing and fly.