There are signs that, as in so many areas of modern life, standards of infidelity are in decline. An American congressman called Anthony Weiner has admitted having taken photographs of his crotch and sent them to a number of women he had never met. Here it has been reported that a famous footballer had an affair with his sister-in-law which had resulted in an abortion.
No wonder that audiences are flocking to the Comedy Theatre to see Betrayal, Harold Pinter's famous play from the golden age of adultery, the 1960s, based on his equally famous affair with Joan Bakewell. For the seven years during which they were seeing each other – in the biblical sense – both were glamorous public figures, yet they managed to keep their love out of the public gaze. When, eventually, some of their friends realised what was going on, they took a grown-up approach and kept a discreet silence.
"There was something different about life then," Bakewell wrote this weekend. "People had a sense of the right to privacy... It was assumed that affairs arose from the dynamic of human relations – the unavoidable attraction of more than one person in one's life – and were viewed benignly until people began to get hurt."
Since those days, infidelity has rather gone off the rails. It may be that, away from priapic footballers and weinering politicians, some honourable affairs, passionate and sad, are taking place, but Bakewell is right: the attitude which surrounds the love life of others has changed. The sense of sympathy, the awareness that, even in the best-ordered lives, people can fall in love with the wrong person at the wrong time, has faded. The modern view is prim and unforgiving. We are fascinated by the sex lives of others but, even as we ogle, we tend to take a position of bogus moral superiority.
A man who messes up his marriage by falling in love with another woman is, it is unquestioningly assumed, a rat of misbehaviour who should forever be distrusted. The career of Robin Cook never quite recovered from the way his marriage ended, and that of Chris Huhne may be heading in the same direction.
The betrayed wife is offered an unattractive choice. Either she can make a career out of her victimhood, writing about the awfulness of men in public life every time a new scandal appears in the press. On the other hand, if she fails to rage and vow revenge in a satisfactory manner, she is likely to be treated with particular contempt. She is a doormat, that undignified and old-fashioned thing, the Stand-By-Your-Man wife.
Even when public marriages come to an end in an apparently civilized fashion, as in the recent case of Trevor Nunn and Imogen Stubbs, the public view of them is sceptical, faintly incredulous.
Some might argue that we have become more sensitive in recent decades, that we understand the pain and hurt which betrayal can cause, and are no longer prepared to stand by and accept it. If we did, we would somehow be complicit in the act of infidelity.
With this new moral vigilantism, a Pinter-Bakewell affair would have not the slightest chance of remaining private. A conscientious friend would feel obliged to have a quiet word with a journalist whose paper, again with the most elevated motives, would run a campaign of disapproving revelation.
These are the morals of a Victorian novelette. Any kind of human muddle involving the competing demands of love, desire, loyalty, fear and daring is reduced to the level of villain or victim, bad or good.
Yet what a shallow, priggish view of love, of men and women, these assumptions represent. How absurd – and how dreary – it is to believe that to be decent and honourable, a person should always live and love according to the same unbending precepts.
As Pinter, like all great writers, knew, there is often something true, tragic and noble in betrayal.