What could be more family-friendly than a Nintendo Wii, a games console replete with motion-sensing technology and gleaming white purity? Just look at the marketing; the families bounding around the living room, gurning with unbridled joy as they compete with each other at video tennis and baseball.

The message is clear; a Wii is the new social hub, it coaxes gloomy teenagers out of their bedrooms and weans them off Grand Theft Auto. Wii players don't buy trench coats and shoot up the local burger bar. A Wii does not warp fragile young minds. In the Wii family, if little Johnny gets tetchy he can always give Daddy a working over on electronic boxing, no harm done. Wii stands for wholesome, healthy family values. It's even got brain training and fitness applications.

So the recent stories about the man in the United States who reportedly filed for divorce, citing his Wii as a catalyst for his wife's infidelity, would have had Nintendo's marketing Svengalis frothing at the mouth.

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Returning from a blood-and-guts deployment in Iraq, the unnamed soldier is said to have plugged in his console, no doubt for some light relief, and uncovered evidence that while he was fighting the insurgency, his wife had been conducting her own secret manoeuvres. You see, a Wii has a gizmo that allows a player to store his or her personal profile, called a Mii. The soldier discovered that his wife's Mii had spent long evenings virtual bowling with another Mii. When he confronted her, she admitted that the mystery Mii was actually a lover. It probably never entered her mind that the games console could be anything but inert.

However, as more and more philanderers are discovering, modern technology has an increasingly unpleasant ability to trip us up, even the whiter-than-white Wii.

In today's world, to function as an effective member of 21st-century society, we have to engage with a bewildering array of electronic gadgets, few of which we fully understand. We stomp digital footprints all over the place, and the unforeseen result of engaging in the information age is that it is becoming harder to have secrets – and, as a result, it is harder to cheat on each other.

Day-to-day actions, such as taking the bus to work and buying a magazine on the way, used to be ephemeral. But today, every journey, every communication, every penny spent, is logged and stored. As we move through life, we leave millions of specks of electronic evidence. Stored on hard drives and mainframes, this data acts like specks of DNA sprayed across the bedsheet of cyberspace. It's all there waiting to incriminate us.

In the face of our know-it-all culture, extramarital affairs do not stand a chance. They are becoming impossible to maintain. Those classic long-running infidelities of the Seventies and Eighties are dying, gradually killed off by the rise of the machines that sit quietly in the corners of our rooms, their beady LED indicators flickering malevolently, storing information about our thoughts and habits, ready to use it as a weapon against us.

As science drags us forward, it's a safe prediction that within the next decade, traditional affairs – the ones with longevity, the ones that take planning, scheming and logistics – will have vanished altogether.

The evidence is already mounting. The number of divorces where adultery is cited as the reason for the marriage break-up is dropping. From 2005 to 2006, the number of divorces granted in the UK fell by 4.5 per cent to 148,141, from 155,052, the second consecutive drop and the lowest number since 1977. Last year, just 29 per cent of divorces happened as a consequence of an affair, down 3 per cent on the previous year.

Affairs are getting shorter, too. Currently, the most common duration of an affair is less than six months (68 per cent of them). Twenty years ago, it was three years.

Affairs are fizzling out, and the change is recent. If the final years of this decade are sounding the death-knell for the affair, the late Nineties and early Noughties were its zenith – and ever-cheaper technology was the fuel philanderers used to stoke the flames of desire. Increasingly available technology – mobile phones, SMS messages, internet connections, BlackBerrys and Bluetooth – made it easier than ever to make contact and stay in touch. "Technosexuals" used phones, email and the internet to hook up with partners for easy encounters. Bluetooth allowed the unfaithful to pick out potential partners on trains and in bars. Research by the London School of Economics found that a quarter of mobile-phone users sent sexually explicit text messages, and one in six people flirted with someone who was not their partner via their phones.

As home PCs became affordable, huge numbers of the populace went online. Through websites such as Friends Reunited, we started to seek out long-forgotten friends, often for romantic reasons. The same story was played out in homes across the globe. Bored husbands and housewives, hypnotised by Windows 95 and the wonders of a 24-bit per second dial-up internet connection, would wobble along the information superhighway from the comfort of the spare bedroom, track down high-school sweethearts and start affairs. Six month later, the marriage would be over. Luddites didn't stand a chance.

Even the England goalkeeper David James succumbed to the lure of Friends Reunited and walked out on his 13-year marriage after rekindling an affair with an old flame through the nostalgia-driven website.

Friends Reunited, launched in 1999, was arguably the first mainstream social networking site. More than 15 million people subscribed. It was suddenly easy for any Tom, Dick or Harriet stuck in a loveless marriage to try to revive the carefree romances of their youth. Friendships that had lapsed decades ago were dusted off, and affairs were inevitably started.

It became easier than ever to find people to cheat with. At the same time, the logistics of an affair also became easier, thanks to burgeoning communications technology. The very structure of the way we communicate with each other changed. Personal mobile phones outsold home phones; text messaging abbreviations crept into standard language; kisses at the end of communications became common; emails replaced "snail mail" and then replaced telephone calls; and finally, face-to-face conversations diminished as office workers began emailing colleagues sitting next to them rather than speaking to them.

On the internet, social networking spurred a new dotcom bonanza, with sites such as Facebook, Bebo and MySpace. The number of sites dedicated to facilitating relationships rocketed. Sites such as marriedsecrets.com, illicitencounters.com and meet2cheat.co.uk, not to mention the personals sections on sites such as Craigslist and Gumtree, all served to help people conduct affairs. Casual postings on these sites rose by a nationwide average of 230 per cent between January and May last year. Groups sprang up on Facebook with names like "Casual sex is the new first base" and "Be my fuck buddy". Webcams built into Wi-Fi-equipped laptops made real-time mobile video communication a reality.

And it won't stop there. The BT futurologist Ian Pearson predicts that in the next 10 to 15 years urban positioning technology will mean that you can text an attractive person in a bar just by pointing your phone at them. He also predicts the rise of technology such as "ego-badges"; jewellery-like devices on which you will be able to upload personal information for transmission to passers-by.

It would seem to follow from this that it should be bonanza time for the affair as far as the young, digital generation is concerned. But the figures suggest not. Rates of younger marriages failing are actually dropping, and the reason is simple – while technology has made it easier to meet and communicate with people, it makes the secrecy needed to conduct an affair almost impossible. There are just too many ways to get caught, and the technology-savvy realise this. Back when maintaining a double life involved simply a call from a phone box and a secret rendezvous point, there were very few tracks to cover. Today, it's almost impossible to do anything in secret.

Say you work in London and use public transport. Like five million Londoners, you have a pre-paid Oyster card to travel; the blue "smart card" introduced by the former mayor Ken Livingstone in 2003. Oyster cards record the dates and times of all journeys taken by the holder, and a record of the previous 10 weeks' travel can easily be seen by entering the card's serial number on a website. So, if you lie to your spouse and tell her you were working late last Thursday, she can easily check if you're telling the truth.

As one private investigator remarked: "An Oyster card won't tell you if someone has been cheating on his wife, but it will show if he's been in one part of town when he's supposed to be somewhere else. It's an easy thing to confront your partner with. It doesn't look like you've been snooping around too much."

Oyster cards are just the tip of the iceberg. Anyone with a rudimentary knowledge of computers can find out what websites have been accessed by sniffing out web history, temporary files and cache records. It's easy to check a mobile phone to see what text messages have been sent and received and what numbers have been called. A quick look at someone's Facebook profile tells you what company they've been keeping, what they've been up to, even how they are feeling.

Snooping has never been easier – and this is just for the beginners. Surveillance technology is now so widely available that anyone can spy on a partner with gadgets and software that James Bond would be proud of.

There is now a whole industry feeding off the insecurities of suspicious people desperate to know if their partners are cheating. Computer software can secretly record all the actions and keystrokes on a PC so that snoops can monitor emails, websites visited and documents created. For a few pounds, you can buy several gadgets that read mobile-phone SIM cards and recover deleted messages.

You can even buy kits online that detect semen; the makers recommend checking not just underwear, but socks and bedsheets as well. A gizmo called the Love Detector uses voice analysis technology to evaluate how your partner feels about you. For the hardcore spy, a £500 Miniature Covert GPS Tracker can be hidden in a car, recording its location via mobile phone signals and storing that data on a memory chip. And for the really paranoid, there's the mobile phone service that uses tiny wireless cameras concealed around the home to record video footage and send it live to your mobile.

So, once you start an affair, at the first whiff of suspicion your partner has a frightening arsenal of state-of-the-art technology with which to catch you. And once you've been caught, modern technology makes it much easier to punish you publicly, too.

Because we can all connect with and contribute to the internet, it now offers jilted lovers the ideal platform on which to air dirty laundry – quite literally, earlier this month, for the wife of a cheating husband who put a photo of his lover's lacy underwear on eBay. The listing, by annastella007 in Canberra, Australia, said the lingerie was "so huge it may make a nice shawl". It was offered for sale with an empty condom wrapper – "size small" – the wife found in their bed. Naming and shaming has gone global.

Wronged partners have spurred a cottage industry in cyber-revenge. Love rats have been humiliated on websites such as myexwifesabitch.com and www.cheated-on.com, which was set up four years ago by Susan Hughes from Devon after she discovered her RAF pilot boyfriend was married.

The latest revenge site, www.liarscheatsandbastards.co.uk, has a section titled Lying Cheating Bastard of the Month. The reality of the global information age is such that, even in a country such as China, where internet access is controlled, web browsers can log on to Liars Cheats and Bastards and discover that John Humphreys from Margate, aka Johnny Boy, has a mark on his chest that resembles a third nipple, and that he allegedly cheated on his now ex-wife with one of her friends. According to the site, he is now in Melbourne, Australia, working on computer games. He probably fled there to escape the humiliation.

Relationship experts and marriage counsellors are now seeing indications of a sea change in the way people cheat, driven by the relentless advance of technology. Andrew G Marshall, a psychologist, wrote: "While starting to cheat might be simple, keeping an affair going has become almost impossible. I would regularly counsel couples where an affair had lasted more than three years. Today, he or she will first get proof and confront. The result is that the length of affairs has dropped dramatically. Looking at all the evidence, it seems that the end of the secret affair is in sight."

There is, however, one anomaly in the data, one area where the affair is holding out and even striking back, and that is in the baby-boomer generation. It seems that it was the post-war generation that got to cheat with impunity, and recent research suggests they are still at it.

A study conducted by researchers at the University of New Hampshire found that the likelihood of a man having an affair now peaks at the age of 55. Older generations, less engaged with modern technology, leave fewer traces when they cheat and are less likely to get caught. For them, cheating is still a viable option.

Divorce figures bear this out. Growing numbers of break-ups in long-established marriages are having a marked effect on divorce rates, which were traditionally dominated by younger couples. While rates of young couples divorcing are decreasing, couples married for more than 30 years are now twice as likely to divorce as they were 10 years ago. In 1996, there were 16,700 divorces involving men in their fifties. In 2006, that figure had risen to 24,700.

Of course, affairs are not always the reason for a divorce, but they feature increasingly in broken long-term marriages as, in a population staying active and healthier for longer, marriages are lasting perhaps decades longer too. So there is an increasing chance that couples will get bored with each other in later life.

Older generations are also more financially secure, thanks to the property boom of the past 30 years, so divorce is less of a financial issue. Add to this mix Viagra and other drugs that help men to stay sexually active, and Botox and cosmetic procedures that help women look younger, and you have a generation not yet ready to give up on extramarital activity.

In contrast, younger people are now leaving it later in life to get married, which means it is more likely that when they do get hitched, they will have found the right partner and will be less likely to stray. Marital relationships and communication between the sexes have also changed in the past 30 years; there is more equality between partners, more empathy, and men and women communicate more than they did 30 or 40 years ago when marriage was often simply a route out of your parents' house. Women's independence and empowerment has meant that marriage is now a choice rather than a necessity for most brides, so most partnerships begin from a healthier starting point.

All this bodes well for the ever-decreasing numbers of people who do marry, but it leaves the prognosis for the affair looking decidedly shaky. In fact, whereas in the later part of the last century, having an affair was seen as a misdemeanour and treated with nudge-nudge-wink-wink sniggers in films and sitcoms (how many of us have sat transfixed in front of shows like Trisha, astonished at the convoluted mess some people manage to make of their private lives?), there is now evidence of a moral backlash against philanderers and a puritanical zeal that does not tolerate cheats.

Earlier this year, the author Mira Kirshenbaum, clinical director of the Chestnut Hill Institute in Boston, a centre for relationship therapy and research, caused moral indignation with her book When Good People Have Affairs, her 11th self-help volume. In it, she dared to suggest that decent people have affairs and that, in some instances, infidelity can help marriages. She was roundly criticised by her peers for suggesting that adulterers deserve sympathy; one said: "Adulterers are neither kind nor good people, so what sort of sympathy are we supposed to give them? A good person doesn't betray their loved ones."

Especially not, it seems, if that good person has a high chance of being found out.