For a young man, there are few pleasures more complete than those that are to be had from sharing your house with another single man. Beer cans are crushed on foreheads, drunk women are brought home by even drunker men, and no food is eaten that hasn’t arrived on the back of a moped and isn’t served from a tinfoil container.

Oh, what joy it is to be alive and living with blokes in those heady days of your twenties. And it isn’t that bad in your thirties, either. But once you get over 35 . . . Well, it starts to look a little suspicious, what one writer referred to recently as the land of the “male spinster”. And, increasingly, women are seeing men who never settle down as not so much “intriguing” as “worrying”.

According to the American sociologist Michael Kimmel, this is the territory of Guyland, and in his recent book of the same name he calls it “the perilous world where boys become men”. Guyland is the land where “young men in their late teens and twenties have nothing better to do than hang out and brag about how much they drank the previous night, or the random girls they’ve ‘hooked up’ with”.

And a lot of fun it is, too. But at some point you do have to check out of Guyland, and that is what I’ve done recently, albeit somewhat late in life. At one-minute-to-midnight at the end of my thirties, I swapped hooking up for tidying up, and bragging about drinking for being on the receiving end of nagging about drinking.

Yet some never do. More and more, “confirmed bachelor” is not a euphemism for “homosexual”, but a description of slightly sad blokes who won’t give up the game. They think that Guyland is not a state you pass through in your twenties, but somewhere you aspire to live for ever. Women, perhaps rightly, are starting to clock that an unmarried man over 40 is not a playboy, but more likely a loner with serious commitment issues and a huge collection of porn.

Ben, a film sound technician and permanent bachelor at the age of 45, says this: “I never want to settle down, because why should I? I get older every year, but the chicks stay the same age. I can still pull women in their twenties, and besides, once I’ve had ’em I don’t want to see ’em again; the thrill is in the chase.”

Adam, an alternative therapist, says the same thing: “Call me a psychopath, and perhaps I am, but once I’ve had sex with a woman, I can’t stand to talk to her again.” Now that doesn’t sound glamorous, just disturbing — but research shows that more and more men are taking Ben and Adam’s path.

It is a tempting one to follow. Life in Guyland is great until the day you wake up and, well, it just isn’t great any more. For most men, that happens when their married mates reach a critical mass. Being a single guy is loads of fun, even in your late thirties, when smug marrieds outnumber footloose shaggers, as long as there’s enough of you to form a round down the pub to pour scorn on your contemporaries and their conversations about overpriced buggies and out-of-town property bargains.

For me, my revelation that I had overstayed my visa in Guyland came the day my flatmate upped and married — the selfish bastard. Suddenly, I was living alone, looking down the barrel of 40 and thinking, “Am I really going to die alone?” and “How come even takeaways seem to come in a size designed to be eaten by two?”

So you meet someone — in my case, clearly, the love of my life — and suddenly, well, I’d like to say I’ve made a compromise, a trade-off between freedom and domesticity, but I have to say to all my single brethren: it is not. It’s more like swapping a lifestyle that is built for mental ill-health for a life of staggering happiness and just the odd row about who’s turn it is to pay the cleaner.

As Chris Rock said, in the best joke of his recent British gigs: “The choice for men over 35 is simple: live on your own — want to kill yourself. Get married — want to kill your wife.” And sadly (and not at all funnily), we know the statistics for single male suicide bear him out.

A whole raft of research shows that whereas some of society’s longest life expectancies are found among groups of nuns, the shortest are found among single men. Single men die early: they drink more, smoke more and kill themselves more often, whereas single unmarried women live longer than their married sisters. The maths is simple: marriage is bad for women and good for guys.

So what are you gonna do? Not marry just to save some chick’s life? I don’t think so. Marry her and save yourself. It’s every man for himself, and the selfish man has only one choice: if he wants to die happy and old, marry and marry quick. Staying too long in Guyland is for those with a death wish.

Of course, this doesn’t mean that the transition from late-thirties singleton to smug married is without its “decompression sickness” — what one bachelor buddy who got hitched recently calls “the wedding bends”. You have to learn how to listen: and not only to a woman’s problems, but also to loud phone calls to her friends. Just as she will have to learn how to listen to a loud television playing World’s Most Amazing Sporting Disasters and Car Crash Nightmares. And you will have to learn to compromise — something that men living in Guyland never do, because they always want to do the same thing (get drunk, get high, get laid, watch World’s Most Amazing Sporting Disasters ).

But, in return, you get your feet rubbed when you feel stressed, and you get sex on tap. And no matter how much they brag, that is something we know guys in Guyland will never have.