Living together, sometimes as an alternative to marriage, is on the increase worldwide. 'It is an important step in development, not only because it represents commitment but also because it is a public declaration of a sexual relationship,' say DeLamater and Friedrich.

According to one American study, however, these relationships tend to be short-lived: One third last less than a year and only one in 10 survives the first five years. Marriage remains the most common sexual lifestyle, and by the age of 45, most women have been married at least once. Apparently, the 'average couple' has sex two to three times a week, but at the same time, say researchers, 'there is great variability in frequency.' Simply put, it means some are doing it seven times a week, and some are only doing it once a month.

SETTLED OR SWINGING?

According to DeLamater and Friedrich, sexual frequency in marriage reflects the joint influence of biological and social factors. There is a decline in sexual frequency with age and the biological reasons include physical changes and chronic illness. Social factors, like getting used to sex with one partner or being unhappy in the relationship, could play an equally important part. Most mothers would attest to a dip in their sex life because of tiredness related to the strains of child-rearing and working.

Couples report having all kinds of sex apart from vaginal intercourse. Almost three-quarters have oral-genital sex, a small n umber have anal sex and many go for hand-genital stimulation. Many adults –including women –continue to masturbate, sometimes once a week, even when they're in a long-term relationship. In their book Becoming Orgasmic, Julia Heiman and Joseph LoPiccolo say masturbation is common among mature people – whether married or not:' Rather than being "abnormal", masturbation is just another frequent and natural expression of sexuality.'

Satisfaction with one's sexual relationship is an important component of sexual health, and although many factors may contribute to satisfaction, these three differentiate people who're happy from those who aren't: Accepting one's own sexuality Listening to one's partner and being a ware of his or her likes and dislikes Talking openly and honestly.

'In other words, successfully completing the developmental tasks of adolescence and young adulthood are keys to sexual health ,' say DeLamater and Friedrich. Most couples experience fundamental changes in their sexual experience at least once over the course of the relationship. The changes may result from dev eloping greater understanding of yourself or your partner, changes in the way you communicate with one another, accidents or illnesses that interfere with sexual responsiveness, or major stressors associated with family and career.

'Some couples will need professional support to enable them to successfully cope with these forces,' says Pretoria psychologist Sandra Murphy. Extramarital sexual activity is not unusual and the most common reasons for this seem to be: Dissatisfaction with marital sexuality Dissatisfaction with or conflicts in the marriage Placing greater emphasis on personal growth and pleasure than on fidelity. Divorced or widowed people have the option of 'post-marital' sex. Most divorced women, and some widows, develop An active sex life, but it's more likely for those who a re under 35 or have no children in the home.

THE LATE BLOOMERS

Biology, so important during childhood and adolescence, begins to have a major influence again at midlife. In women, menopause is associated with a decline in the production of oestrogen. This means, among other things , that intercourse could become uncomfortable as the vagina walls become thin and inelastic, the vagina shrinks in width and length and vaginal lubrication decreases noticeably. Experts are greed, though, that these changes don't mean you won't havea satisfying sex life after menopause.

'Among older people who are healthy and active and have regular opportunities for sexual expression, sexual activity in all forms –including masturbation and same-gender behaviour –continues past 74 years of age, ' say DeLamater and Friedrich. Authors Heiman and LoPiccolo say that 'if a woman believes that she is less sexual because she is growing older, she will indeed feel less sexual and probably experience diminished sexual responsiveness, for purely psychological reasons.'

There is a strong cultural myth that old people shouldn't, can't or don't want to have sex. But they can –and they do. Murphy says GPs sometimes report that their re tired patients Experience a surge in their marital sex life. 'Re tired people suddenly have more time and less stress and, happily for many couples, this can lead to an increase in sexual activity, ' she says.

In the final analysis, how your sex life matures and whether it fulfils you have to do with a lot more than mere physiology or the reams of sex manuals available from book stores. It's about being comfortable in your body and with yourself. Kitzinger says,' Any dogma about how we should feel and ex press ours elves through our bodies can degrade sex.'

'It's about being authentic, about loving ourselves and taking ourselves seriously. Sex is an expression of yourself, it's about how you feel about you ,' says Marion Campbell. ' It's about an inter change of energy that is only tangentially related to genitals and biological processes.'

Image: True Love/ Vanessa Grobler