Jane was 19 when she married, but he was the man she loved and expected to live with for the rest of her life. The caterer, from Edinburgh, grew up in a society where marriages were built to last. It didn’t occur to her that she and her husband would change, along with the attitudes of their generation.

Now in her forties, she has been separated from her husband for four years after she embarked on an affair with a man she met through work. Her motivations may have been complex, but they were undeniably connected with sex.

The joke when she was growing up in her suburban neighbourhood was that sex was what the coal arrived in. It was a practice that went on behind closed doors and was never referred to in polite company. But things have changed, not least for Jane.

“My husband was 12 years older than me and everything had gone stale. He had his golf and his interests. I think he just expected me to be the good housewife,” she said.

“The man with whom I had an affair came into my life through work and it was wonderful. It gave me that spark back.”

Now she admits her attitude to sex and relationships is more liberal than ever. “I don’t think you can point blank say adultery is morally unacceptable. People react differently to different things. I know that I never set out to have an affair — but it happened.”

Caught between the twin pillars of Presbyterianism and Roman Catholicism, Scots have long harboured an ascetic attitude to sex. Double standards and sexual inhibition are ingrained features of Scottish cultural life, from Robert Burns’s poem Holy Willie’s Prayer (O Lord! confess I must: At times I’m fash’d wi fleshly lust; An’ sometimes, too, in warldly trust, Vile self gets in) to modern-day comics such as Billy Connolly and the late Rikki Fulton’s joyless creation, the Presbyterian Rev IM Jolly.

The 18th century may have been a time of sexual liberalism, with sex clubs operating with impunity in Scotland’s capital, but the Victorian era brought a moral backlash from which much of Scotland didn’t recover until late into the 20th century.

“Scotland’s attitudes to sex stem from the reformation when the Protestants reacted strongly against the lax attitudes of the Catholic church.

“In those days the priest was far from chaste. It’s odd how things change,” said Professor David Stevenson, a social historian at St Andrews University.

However, a new poll commissioned by The Sunday Times suggests attitudes are softening.

While issues such as pornography, prostitution and adultery have yet to breach mainstream acceptability, in private at least, people admit to being more relaxed about them than ever before.

The YouGov poll reveals fewer than half of Scots believe infidelity is morally wrong. Only one-third thought that being a prostitute was wrong — in 2002 about 35% said it should be illegal.

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