Suzi Godson

About five o'clock on most Friday afternoons, happily married men all over Britain call their wives and tell them that they still have a few things to finish at the office.

They indulge in a couple of minutes of routine chit-chat “Had a nice day?” or “Kids all right?” and then they mention, casually, that there is a chance they might go for a quick beer with the guys after work. The woman knows the score. She sighs and says “OK”. Her husband gushes a heartfelt “I love you” and then he hangs up, victorious.

These conversations are, to some degree, a mutual conspiracy because the wife realises from the start that the entire exchange is a ploy for her husband to get a pass out for the evening. It is not unreasonable. He needs to let off some steam and she knows that he will come home pissed, penitent and a little more patient with the children, so she plays along.

What she doesn't know, or doesn't want to consider, is the fact that all over Britain on a Friday afternoon, single working women are in the office loos putting on their make-up so that they can look hot when they join the guys in the pub after work.

Of course they know who is and isn't available, but those pub glasses of chardonnay are enormous and, after a pint of wine, it gets easier to believe that “he wouldn't be in the pub chatting to me every Friday night if he was really happily married, would he?”

British people work the longest hours in Europe, which means that if you don't include the hours spent sleeping, couples often spend more time with the people in their office with than they

do with each other. Toss in Friday night at the pub and men like you are channelling the vast majority of your energy into secondary relationships - at the expense of your wife and family.

It's common knowledge that affairs usually begin with an attraction to someone you spend a lot of time with - colleagues, clients, confidantes, that kind of thing. Assigning any kind of sexual fantasy to young women that you work with or see regularly doesn't bode well for your marriage.

You may think that you are simply getting a thrill out of the fact that you can wind them up and reel them in, but seduction is not a game.

Invest enough time and energy in any “we're just good friends” relationship outside your marriage, liberally drench it with alcohol, and sex becomes less of a possibility and more of a probability.

Good marriages are based on trust. It is faith in fidelity that allows married men and women to give each other unconditional independence and, although you are not technically cheating on your wife, the fact that you could not dream of sharing this revelation with her suggests that you know she would feel threatened by it.

Being in a relationship doesn't stop a man finding other women attractive, but a man who really values his partner is usually smart enough to give temptation a wide berth. On a Friday night he goes home instead of going to the pub, and the next morning he wakes up with a clear head and a clean conscience next to the one he loves.

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

Dr Thomas Stuttaford

A generation ago we were brought up to believe that men were promiscuous by nature, ready at all times to hand on their genes by mating with any available woman. As a result, they were assumed to behave as lascivious brutes if they were given any encouragement, even if it was only the sight of a pretty girl.

They were not blamed for this characteristic; it was thought to be an animal urge that they had to fight to resist. After all, it was only swans who mated for life and were thereafter forever faithful. But a pair of swans that lived on a nearby mill pond when I was younger taught me that all male swans certainly didn't pine to death if their mate died. When our male swan was left alone, he found another partner almost immediately.

People of my age were also programmed to believe that it was a woman's destiny to look after the house and care for children, an opinion that, I admit, was based on fast-disappearing stereotypes and dated mores.

Even so, the differences in sexual drive between men and women can be explained. Many stem, for instance, from how women are brought up, and a justified fear of pregnancy, especially in the days before the Pill.

But it is no longer accepted that nature kits out all women with the necessary hormones and mindsets to give them a romantic approach to life that leads to marriage, monogamy and happiness. But neither are all men born sinners.

A French patient described behaviour just like yours and told me that he couldn't understand why this was considered a problem in Britain. In the Gallic world if a man did not look at and assess other women he was considered to be “dead or dying”. He also suggested that there was a big difference between window-shopping and being a spendthrift who wanted to buy everything on view.

He told me that he and, apparently, his fellow countrymen were surprised that men and women in London didn't size each other up as they did in Paris. The only question was whether British men were more spiritually inclined than those in France, or had less testosterone!

If most women are not as obsessed by how men look as the other way around, it is not entirely because they are scheduled to become enthusiastic mothers and home- makers. Sometimes it is because women are not as visual as men when assessing possible partners.

Although smell is less important in human beings than in most animals for seduction, the balance of visual and olfactory stimulation is different between the sexes.

Women are more influenced by other factors. They need to know more about a man than surreptitious glances at his biceps, chest and hips reveal. Will he be sensitive, reliable and a good provider? As they are less visual, women find it hard to understand why men are so influenced by looks. You are normal, if indiscreet.

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

Times recommends

• Live fashion advice: how to dress for party season
• The A-Z of winter style rules
• Could safe havens prevent teenage stabbings?