'We have sex, we chat, we go back to our families,' Sheila tells me over a cappuccino.'I'm not looking for a soul mate, I'm looking for physical release. The girls were small and sex with him had long been just another chore, like loading the dishwasher.
But today the guilt that tormented these classic heroines is largely missing.
One of the challenges Sheila hadn't expected was where to hide her sexy lingerie.
'I went out and spent a fortune at Myla on gorgeous transparent bras and G-strings – things I'd stopped wearing for my husband, Peter, even before we were married.
But once every fortnight or so she tells Peter, 48, a company director, that she's meeting a (well-briefed) girlfriend for dinner.
Instead she goes to a motel room to see her lover, Michael, also 46, a medical sales rep whom she met at a conference.
Thousands of women like Sheila are enjoying what they believe to be no-strings flings. Some of my friends ride, some sing in choirs, I have Michael.' The number of people having affairs is impossible to know, as few are truthful about their sex lives, but the recent Way We Are Now nationwide survey conducted by Relate showed that 34 per cent of women respondents admitted to being unfaithful, compared with 32 per cent of men.