He lives a strange life, moving between homes, all furnished and decorated in exactly the same way, with white leather sofas and chrome mirrors, trailed by an entourage of close friends and acolytes.
This lifestyle has generally suited Cowell well, facilitating both his oddities and his sweaty hyper-devotion to work. At the same time it has fed the idea that he is not merely, as he has put it, "a little bit mad", but sad, too, and emotionally cauterised against the perils of love and human sympathy.
Virtually all his known relationships have been brief and inconsequential, and are collectively summarised by him as "boring".
It is no surprise the idea of fatherhood has drained the blood from his chops.
"God, no, I couldn't have children," he once said. "If I had them they'd be drawing on the walls, and I'd go nuts. With kids you've got a routine you can't escape from."
Not that Cowell is entirely opposed to routines. Having attuned his life to a kind of mid-Atlantic time, he wakes up every day at noon, spends an hour watching cartoons, usually in the bath, then works, with only token breaks, until 5am.
All his suits are by Tom Ford, all his knitwear from Prada. His beauty regime is exhaustive, featuring colonic irrigation, which, he says, "makes my eyes shine brighter", intravenous vitamin transfusions, monthly botox jabs, and a procedure involving oils and cling film to "detoxify and oxygenate" his skin. To keep the air fresh he spends 3000 ($5800) a week on flowers.
"Maintenance," he sighs, "is a bitch." But so is growing older, especially when you have no one to share the passing years with.
So there may come a moment in a man's life when he starts to think about his legacy, and how he will be remembered, and he realises that children can offer a handy solution.
Cowell has known the Silvermans, who have a 7-year-old son, for several years. Two years ago, the couple were among the guests on a yacht the impresario had chartered in the British Virgin Islands.
Lauren Silverman posted a photograph of herself entwined with Cowell beneath the caption: "My little Simey monster," which she later deleted.
Cowell's reluctance to embrace commitment has no obvious explanation in his own childhood. He was born in Brighton into a close and relatively well-to-do family. His father ran the property portfolio of EMI records, and his mother was a former dancer.
His older half-brother, Tony, remembers him as a "highly competitive teenager", who "always wanted a faster car and a prettier girlfriend".
Privately schooled at Dover College, Cowell achieved little of academic note and left at 15 to take a job in the post room of his father's firm.
Soon he was a pop industry talent scout, working with the famed record producer Pete Waterman.
By the age of 20, he had made - and lost - a million.
His move into television and the following successes - Pop Idol, The X Factor, Britain's Got Talent - have earned Cowell a fortune estimated at 200 million and secured his place as the most powerful man in British entertainment. Yet the narcissism, the affectations, the detachment, the lack of gallantry (his relationship with Dannii Minogue was dismissed as "a few bonks") have weighed heavily against this.
But he remains a master of the tricky situation, and if he handles the latest properly, he might yet emerge as a better man.
