IN a world where certain celebrity underpants seem to be permanently round their ankles comes, at last, an unlikely glimmer of hope.

Hugh Hefner, a man who admits he stopped counting his girlfriends a long time ago, has said he believes monogamy is possible.

The octogenarian Playboy founder, due to get married to the third Mrs Hefner -- 24-year-old former playmate Crystal Harris -- this Saturday, insists his nuptials will mark the end of his carousing.

As improbable a poster boy as Hefner may seem, his conversion is a high point in what’s been a tough year for monogamy so far. First Charlie Sheen unveiled his two live-in girlfriends, declaring that polyamory is where it’s at.

Then there was the Ryan Giggs affair, while Arnold Schwarzenegger was revealed to have fathered a love-child with his family housekeeper under the nose of his wife of 25 years.

Last week, Pamela Stephenson admitted to turning a blind eye to any possible indiscretions by her husband Billy Connolly. “I don’t ask [about other women] and I don’t care,” she says. “I think monogamy’s hard for anybody.”

As for Hefner, he has dabbled in monogamy before. After marrying his second wife in 1989, the notorious Playboy Mansion was transformed into a family-friendly environment. When the couple separated in 1998, Hefner promptly reverted to his old ways.

While cynics may suggest that citing monogamy is merely saving face for a man of 85 looking to slow down in his latter years, romantics will argue that it’s simply taken Hefner the best part of nine decades to find his soulmate.

For many people, though, monogamy appears to be increasingly confused with monotony: boredom leading to a wandering eye.

But before monogamy goes the way of the proverbial Dodo, let’s suspend our disbelief for a moment. Say Hefner actually pulls it off. Could this inspire a whole new generation of men into coveting fidelity as the holy grail?

It’s a nice notion. But, then, so are fairies at the bottom of the garden -- and altogether more plausible.