MOST people in steady relationships occasionally wonder what it would be like to make love with someone different.

It's not easy to keep your sex-life feeling fresh and exciting for year after year, and swapping partners for the odd night can sound like the best way to sharpen up your appetite without risking your relationship.

After all, if you're both doing it openly, the argument runs, what can be the harm?

It doesn't involve deceit, like an affair, and you both have fun.

The Internet has vastly increased the ease with which you can make contact with other potential swingers, and you can find dogging sites within a few metres with a few clicks of the mouse. All very simple.

Unfortunately, it's not as simple as that. Human beings are not just animals.

Our sex life is closely linked with our emotions. Making love with a partner can be difficult to keep separate from feeling in love with them.

What can be safe as a fantasy can be very risky for our relationships when we get real people involved.

Judging by the readers who get in touch with me, it is usually the man in a couple who is pressing to try swapping and swinging.

In fact, men are often more capable than women of just having sex without getting emotionally involved.

But their excitement at the idea of acting out their fantasy often blinds them to the risks they are running in reality.

To start with, they may feel confident that they can have sex with the other woman without it threatening their love for their partner, but can find they react very differently afterwards about their partner having made love with another man.

Even if she was reluctant and they pressured her like mad to agree to swapping, they can react - completely unfairly - by being very jealous and asking how she could bear to make love to anyone else.

And whatever the woman's experience, it's bad news.

If she has a rotten time, then she will feel dirtied and resentful that her partner made her take part - and perhaps be left feeling very insecure if he enjoyed himself.

If she has a good time, her partner may well be the one left feeling insecure.

Most men feel very vulnerable if there's a chance their prowess as a lover may not compare favourably.

And since women tend to feel emotionally drawn to someone who makes them feel special in bed, there is also a risk that they will fall for the other man.

In fact, the risk of someone falling for the other partner applies all round, of course, and a very painful emotional mess can follow, with not only the adults involved getting hurt but any children they may have too.

So this supposed safe way of you both enjoying sex with someone new can result in two broken relationships, wrecked families and a lot of grief - and that's quite apart from the physical risks that having sex outside your committed relationship can bring.

Suppose one of the other couple is harbouring a sexual infection - people can pass on an infection such as chlamydia or gonorrhoea even though they are not experiencing any symptoms and aren't aware they've got it.

Sexual infections can result in infertility, so it's not a risk to take lightly.

Or suppose there is a contraception failure and one of the women gets pregnant?

If you are absolutely determined to try swapping or swinging, you do need to make extra-sure of your contraceptive precautions and follow the guidelines for safer sex, using condoms and so on.

But I'd recommend you instead look more deeply at what is leading you - or your partner - to feel drawn to the idea.

Is it that your love life has become rather dull or unsatisfying?

This could be because you have a sexual problem which needs sorting out - difficulty in reaching orgasm or maintaining an erection, for example.

If so, please let me know and I can send you free leaflets giving details of self-help and expert sex therapy.

It could be there is some tension in your relationship which needs sorting out. As I've said, our sex lives and our feelings are closely linked.

Difficulties in our sexual relationship are very often symptoms of more general problems.

A woman who is always tired out because she shoulders most of the chores at home as well as having a paid job, for example, will lose interest in sex.

A man who is overwhelmed with worries about holding on to his job may well find his sex drive crashes.

Internet site reference: http://www.thesun.co.uk/sol/homepage/deidre/sextherapy/2320489/Dear-Deidre-sex-therapy-Swapping-and-swinging.html