Q I'm a 42-year-old man in love with a beautiful fiftysomething woman. She says we don't have a future together because of the age gap. Is she right?

DR THOMAS STUTTAFORD

A When Benjamin Disraeli, the Victorian statesman, married a woman appreciably older than he was, eyebrows were raised. But the Queen, society and his fellow politicians soon accepted it. Now, when the actress Tilda Swinton, who is in her mid-forties, travels the world with a much younger man, the age difference seems immaterial.

Unfortunately, we don't know whether your lover is 9 or 17 years older than you are, whether she is nearly 60 or only 50. Ten years one way or the other doesn't alter the principle that, in the short term, the age of a partner doesn't matter a damn, so long as you are both happy. However, your lover makes an important point that a wide age gap could in the long term alter the future of your relationship. If you had planned to have children, it could be that any strong desire for fatherhood and the perpetuation of your genes has been temporarily assuaged by the initial lustful stage of a new relationship. However, in later years, when your marriage should have been moving easily into the stages of acceptance and deep friendship that characterises long relationships, the lack of a family and long-founded joint interests might cause strains and resentments. These could lead to you regretting your decision.

Everyone knows people who have married older partners. Some of these unions have been outstandingly successful and the couple's happiness together has never waned. In other cases, once the elder of the two becomes infirm, the difference in age may cause resentments.

It is worrying that you place such emphasis on your partner's beauty, although “fiftysomething”. Ageing can't be disguised for ever and intellectual behaviour as well as physique are bound to change with increasing years. It is more difficult to hide a failing memory, slower reactions and increasing conservatism than it is to Botox away wrinkles or suck out excess fat.

When an affair is as new, sensuous and passionate as yours seems to be, it is difficult to make a detached appraisal of it. The obsessional nature of love can extinguish reason but, despite this, your lover has obviously been analysing your relationship and you need to do so as well. You have to ask yourself what the basis of your mutual attraction is. It could be that for both of you it is mainly lust, and whereas your partner knows this, accepts it and even hints about it to you, you deny it.

If she is nearly 60, she may be dreading even the possibility of a slippers-by-the-fireside existence. The arrival of an outlet for her libido in the form of a comparatively young man, who not only desires her sexually but seems to be committed to her, might well have seemed like a lifebelt. Conversely, she may see your relationship as sex with friendship and might even be beginning to fear that long-term commitment to a younger person would be demanding, tiring and restrict her freedom.

Or possibly, like a female celebrity, she sees an attentive handsome younger man as a status symbol, a trophy that reflects her success to her contemporaries. In the past older men enjoyed the look of envy that a younger, pretty woman on their arm inspired in male colleagues. So why deny this pleasure to women?

Dr Thomas Stuttaford, The Times doctor, spent many years working in a genitourinary clinic

SUZI GODSON

A She is lucky to have found you. Men tend to date downwards and the older a woman gets the harder it is for her to find a partner. It's a trend that is changing. The US National Association of Retired Persons surveyed its members a couple of years ago and found that 34 per cent of all women over 40 were dating younger men. But, by and large, women who are single in their mid to late-fifties find it much harder to get a date than women in their late-thirties.

The average age at which a woman hits menopause is 51. While some women breeze through it, others say that they come out the other side feeling redundant. Besides the deafeningly silent biological clock, women in their mid to late-fifties describe a feeling of invisibility. We live, after all, in a society that worships youth and beauty, and however gorgeous your girlfriend is now, the chances are she feels that she was far more so 20 years ago. Even women as fabulous as Julie Christie, 66, find the ageing process challenging. In a recent interview with The Times, she admitted: “I'm tempted every time I look in the mirror. You want to get your face back when you see all the lines around your chin, neck, eyes, mouth and your bloody arms and everything else.”

Women over 50 are the biggest consumers of cosmetic surgery and they are also more susceptible to long-term depression, but the lucky few, like your girlfriend, find a much more pleasurable way of making themselves feel more attractive. The older woman-younger man relationship works well on so many levels. He gets a more experienced partner. She gets a partner with a higher libido and no love handles. Older women are generally richer. Younger men who may not be so advanced in their careers tend to be less tied down, so they can spend more time with their partner. If you have similar energy levels and you're comfortable with the fact that she is never going to pass for 25, then the only remaining elephant in the room is children.

The desire to procreate may be low on your list of priorities now, but it can sneak up on you out of nowhere. It's no surprise that Demi Moore, 45, and Ashton Kutcher, 30, the poster couple for older woman-younger man relationships, are having a baby. It's an insurance policy for Moore, but it's not something that your girlfriend can consider, so she needs to make sure that you are not going to roll over in six months and tell her that you have always really wanted a handful of kids and a Renault Espace.

Although there is never a guarantee that any relationship will last, the older a woman gets, the less inclined she is to take risks with her mental health. Your girlfriend is raising the stakes (some would say shooting herself in the foot) by forcing you to address your long-term intentions so early in the relationship, but I feel for her. Life is hard and all any of us want is a little love and affection and some sort of guarantee that we won't be hurt or humiliated.

Your beautiful fiftysomething girlfriend isn't saying that you don't have a future together. She is asking you to consider the sacrifices and the benefits of being in a relationship with someone who is technically old enough to have given birth to you. And then she wants you to tell her that what you have always really wanted is her.

Suzi Godson is author of The Sex Book (Cassell, £16.99) and The Body Bible (Penguin, £16.99)

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