Alain de Botton muses on the nature of sex and its immense power over our lives and emotions.

We are unlikely to be able to get a grip on this notorious subject if we don’t first allow ourselves to acknowledge just how tempting and exhilarating adultery can be, especially after a few years of marriage and a couple of children. Before we can begin to call it ‘wrong’, we have to conclude that it is also very often – for a time, at least – profoundly thrilling.

Let’s go even further and venture that (contrary to all public verdicts on adultery), the real fault might consist in the obverse – that is, in the lack of any wish whatsoever to stray. This might be considered not only weird but wrong in the deepest sense of the word, because it is irrational and against nature. A blanket refusal to entertain adulterous possibilities would seem to represent a colossal failure of the imagination, a spoilt imperturbability in the face of the tragically brief span we have been allotted on this earth, a heedless disregard for the glorious fleshy reality of our bodies ... Wouldn’t the rejection of these temptations be itself tantamount to a sort of betrayal? Would it really be possible to trust anyone who never showed any interest at all in being unfaithful?

Too many people start off in relationships by putting the moral emphasis in the wrong place, smugly mocking the urge to stray as if it were something disgusting and unthinkable. But in truth, it is the ability to stay that is both wondrous and worthy of honour, though it is too often simply taken for granted and deemed the normal state of affairs. That a couple should be willing to watch their lives go by from within the cage of marriage, without acting on outside sexual impulses, is a miracle of civilisation and kindness for which they ought both to feel grateful on a daily basis.

There is nothing normal or particularly pleasant about sexual renunciation. Fidelity deserves to be considered an achievement and constantly praised – ideally with some medals and the sounding of a public gong – rather than discounted as an unremarkable norm whose undermining by an affair should provoke spousal rage. A loyal marriage ought at all times to retain within it an awareness of the immense forbearance and generosity that the two parties are mutually showing in managing not to sleep around (and, for that matter, in refraining from killing each other). If one partner should happen to slip, the other might forgo fury in favour of a certain bemused amazement at the stretches of fidelity and calm that the two of them have otherwise succeeded in maintaining against such great odds.

Ultimately, sex gives us problems within marriage because it gives us problems everywhere. Unfortunately, our own private dilemmas around sex in marriage or otherwise are commonly aggravated by the idea that we belong to a liberated age – and ought by now, as a result, to be finding sex a straightforward and untroubling matter.

But despite our best efforts to clean it of its peculiarities, sex will never be simple in the ways we might like it to be. It can die out halfway through a marriage; it refuses to sit neatly on top of love, as it should. Tame it though we may try, sex has a recurring tendency to wreak havoc across our conjugal lives. Sex remains in absurd, and perhaps irreconcilable, conflict with some of our highest commitments and values. Perhaps ultimately we should accept that sex is inherently rather odd instead of blaming ourselves for not responding in more normal ways to its confusing impulses. This is not to say that we cannot take steps to grow wiser about sex. We should simply realise that we will never entirely surmount the difficulties it throws our way.