I was 19 when Laurent Lemoine first asked me to marry him. I told him I was too young — he was 30 — and suggested he ask me again in five years’ time. Ten months later we were married and our first child was on the way, my final year at Oxford postponed.

Laurent’s extraordinary adroitness in pursuing me was one of the most attractive things about him. Until I met him I had known only English boys my own age, who were all infected by a certain erotic timorousness. Most of the time, having sex with them had meant battling my way through their insecurities long before we got anywhere near mine. Laurent’s self-belief was utterly compelling.

I wondered if some of the sexual paralysis afflicting my English male contemporaries was brought on by post-feminist guilt. Two of the boys I had slept with had actually confessed the missionary position made them feel “too dominant”. It soon became clear this was not the kind of complex Laurent suffered from.

Early on in our relationship his hand shot out while we were having sex and slapped me smartly across the face. Supine and submissive as I may have been, the gesture backfired and my desire went out like a light. Laurent wasn’t put off, though. He merely observed that smacks were obviously not my thing and that I shouldn’t feel bad about it. He admitted that he had probably done it out of habit.

In our Anglo-Saxon culture, sex and love have become polarised through guilt. In such a context sex can achieve purification only through love. In the minds of the French middle classes, sex, even where love is absent, is a source of pleasure to which every human being has an inalienable right. This applies to women as well as men. Adultery is widely perceived as one of the principal components of marriage.

The first time Laurent took me out to dinner he spent most of the evening talking about his former girlfriend, Aurélie. Laurent explained that out of the sack Aurélie had bored him but in it she was unsurpassable. Two years into our marriage, David, a friend from Oxford, came to stay. Laurent and I took him to a dinner party given by Aurélie and her new lover, Daniel.

Like all of the women in la bande — the gang Laurent had hung around with since his school days — Aurélie was a good and effortless cook. In a dress that made her perfect body look as if it had been wrapped in black bandages, she flirted with the men and the women with equal commitment, lavishly kissing both on the lips.

The wine flowed; it didn’t gush. People sipped; they didn’t quaff. The evening seemed to be all about men and women and the games they play to entertain each other. In this context, inebriation felt inappropriate, even pointless, since if you became too drunk you would miss the fun.

The fun turned out to be the discreet toing and froing between the dinner table and the divan in the next-door room. What began as a ménage à trois (two girls and a boy) became quatre (two boys and two girls), then cinq (three boys and two girls) and, at the point when we went home to “liberate the babysitter”, a ménage à six.

I noticed that people kept disappearing into the little room, and assumed somebody was showing a film they had made or perhaps watching a Formula One race. David seemed happy talking to someone else, so I went to have a look.

I cannot remember the exact anatomical details but I did register my friend Betty (who had seen a hypnotist for her climaxing difficulties) in a semi-naked human knot with a small male architect (who had learnt his English from Monty Python records) and a female psychiatric nurse (who had already frightened David during dinner by asking him if he liked having sex with strangers).

Betty looked up and smiled sweetly at me and asked if I would like to join them. I said, “No, no, I’m fine,” as coolly as I could and closed the door behind me.

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