What business is it of any of us or his supervisors in Congress that David Petraeus had an affair?

The former general was forced to resign as director of the CIA after the FBI discovered that he had been romantically involved with his biographer Paula Broadwell for four years. Adultery may not be agreeable to many in our increasingly moralising climate, but we should leave judgment and punishment to those on whom his acts directly impact: his wife of 38 years and his family. His personal dalliances (or as he diplomatically called them in his apology, his "mistakes") are not a matter for public concern. His position was not to serve as a role model. His role as director of the CIA was to provide direction for collecting, evaluating and correlating national intelligence for the US. There is no prerequisite for a squeaky-clean lifestyle behind the public scenes.

Yes, he occupied a public post. But he has a right to a private life, private interests and private judgment calls. Yes, the affair came to light during an investigation by the FBI into a potential security breach, but the investigation concluded there was no breach and the "classified information" that Broadwell allegedly came into contact with is not thought to have come from Petraeus.

Sure, it wasn't wise of him to grant his paramour access to his personal Gmail account (apparently so they could send messages to each other). But this should be of no concern to us other than amusement at the results of his naive trust in his mistress. She went on to use it to send catty "back off" messages to another woman she suspected was a love rival. She should have known better. Drama is the last thing any high-profile married lover wants in his mistress.

For sure, the story is gossip-worthy. But worthy of a formal inquiry, which is what some congressmen are now demanding? No. The story is more human interest than public interest.

There have been too many cases where we have lost competent professionals, not because of a failure in their duties, but because of puritanical judgment over their irrelevant personal lives. John Terry lost his England captaincy because of a fling with a fellow teammate's former girlfriend, Vanessa Perroncel. The former Labour MP Ron Davies resigned twice after claims he had casual sex with a gay lover. Tim Yeo was forced to resign when news emerged he'd fathered an illegitimate child. But it is none of anyone's business what sex partners, sex clubs or sex preferences anyone chooses outside of their office, as long as he or she does their job.

Sadly, Americans are even more righteous than Britons when it comes to preserving the image of public figures. Bill Clinton's "lapse in judgment" with Monica Lewinsky led to him facing trial for impeachment even though he'd made no political howlers. If monogamy wasn't so blindly worshipped, Petraeus wouldn't be in trouble at all.

Fidelity is a lifestyle choice and a subjective moral judgment, it is not the law. Many communities turn a blind eye to short-lived extramarital liaisons. Some couples negotiate open arrangements among themselves. Anthropologists accept that monogamy is not the natural human mating strategy. It makes sense for societies to promote fidelity and puritanical family values. It helps keep public order, it simplifies legitimacy laws and it ensures men have unrivalled regular access to a sexual partner.

Across Europe in the middle ages, adulterers would be punished by death or mutilation. Shaming Petraeus in this way echoes the same sort of barbaric social engineering that was common in those times.

Until Friday, Petraeus had a glittering career. He was a four-star general recognised as the architect of the US counterinsurgency strategy in Iraq. Those who encouraged his resignation cut off their nose to spite their face. The headlines and outrage surrounding his affair smacks of sadistic delight at seeing a successful man fall from grace, rather than rational concern for national security. What we should be more alarmed by is our own voyeuristic appetite for salacious tittle-tattle, rather than what senior officials get up to in their private lives.