Carlos Amato: Be honest: do you have a little something happening on the side? And relax, we're not talking about rumpy pumpy here. This is strictly football. To be precise, do you support a second team on the sly, because your dearly beloved club is not meeting your needs?

Football devotees all over the world favour a different team in every well-known league - you'll find plenty of casual, utterly clueless Orlando Pirates fans in Brazil, for example. And it's perfectly legit to have a soft spot for one of your team's direct rivals.

But I'm not asking about these harmless flirtations. The matter at hand is proper, hardcore cheating, complete with emotional infidelity, motel quickies and divorce.

Supporter infidelity popped into my head on Wednesday night at a sleepy Dobsonville stadium, where about 1000 loyal Swallows fans watched their team get mugged 3-2 by Ajax Cape Town.

That's not a scandalously small turnout for the Premiership, but once upon a time, in the late 1980s, the then sexy Dube Birds would have attracted 8000 or 10000 punters for a comparable league match with ease.

Where have all the Swallows fans gone?

Some of them have grown too old and fat for stadium outings. And some are no longer with us. But many have just stopped bothering - or even started supporting one of the Gauteng elite, a category the Birds once inhabited.

Even those who have stayed faithful aren't passing on the Swallows DNA. I spoke to Jacob, a veteran, fortysomething fan who has failed to convince his teenage daughter that Swallows are a brand worth consuming. "She's at home, watching Pirates on TV," he admitted with a rueful smile.

That's the crux: the kids of today don't give a hoot about nostalgia and tradition. In all likelihood, Jacob's daughter fancies Bucs simply because she fancies the hell out of Teko Modise or Dikgang Mabalane, and why not? (Much to my amazement, my teenage cousins don't like football at all, perhaps because it's devoid of CGI animation or vampires.)

Football promiscuity is most extreme in China, the promised land of modern football economics, where tens of millions of "serial fans" switch their allegiances and replica kits in every transfer window. Clubs are as exchangeable as video games or ringtones.

Even in England, the hallowed birthplace of the game, football fandom is gloriously fickle. As Simon Kuper and Stefan Szymanski's book Soccernomics notes, the number of self-described Chelsea fans grew as much as tenfold between 2003, when Roman Abramovich bought the Blues, and 2006, when they won their second title on the trot.

At the time of writing, the official Manchester City Supporters Club of South Africa boasted 37 Facebook members, compared with 1781 members signed up to one of several official Manchester United pages.

The City page will swell soon. When Roberto Mancini's troops win a title (and it's when, not if), a horde of new City fans will appear across the country, like millions of powder-blue Namaqualand daisies.

If you're a loyal, long-suffering Liverpool or Arsenal fan, you will laugh at these fairweather phonies. And they will laugh right back at you, because losers are ridiculous.

• Carlos Amato is the SAB Sports Columnist of the Year