The satisfaction of our needs may force us to ask for things that are, from a distance, open to being judged both ridiculous and contemptible so that we may prefer, in the end, not to entrust them to someone on whom we must rely for so much else in the course of our ordinary, upstanding life.

We should try to locate the good and the beautiful beneath the layers of habit and routine.

The French novelist Stendhal offers us a way out of this scientific cul-de-sac with the maxim ‘Beauty is the promise of happiness’.

Books retain a role in offering us consoling reminders that we are not alone with the humiliating and peculiar difficulties imposed by our unavoidable possession of a sex drive.

The shame begins in adolescence. As our bodies mature and become physically ready for sex, so we run the risk of appearing obscene before the wrong eyes.

The taboo preventing him from announcing to her, ‘I want to love you and look after you tenderly for the rest of my life,’ is just as strong as the one that stops her saying to him, ‘I’d like to fuck you in my motel room and then say goodbye to you for ever.’

What unites the ‘whore’ and the ‘bastard’ in these two scenarios is their emotional and actual unavailability and therefore their power not to act as permanent witnesses to, and evocators of, our sexual vulnerability and strangeness. Sex may sometimes be just too private an activity to engage in with someone we know well and have to see all the tim

To begin with, and most innocently, the paucity of sex within established relationships typically has to do with the difficulty of shifting registers between the everyday and the erotic.

The more horrifying we believe our behaviour would seem to the larger, judgemental society we normally live in, the more we feel as if we are building a paradise of mutual acceptance.