Science tells us that human beings are polygamous by nature, but our hearts often tell us otherwise. Nearly every marriage vow contains the phrase: 'forsaking all others', but over half of all marriages end in divorce and the most common reason cited is infidelity. But some people do seem to manage it and their relationship prospers. So what's their secret?

Monogamous couples trust each other

Dr Diane Iveson is a relationship counsellor who advises couples on maintaining strong and healthy relationships. She claims the starting point for all successful monogamous couples is trust. "Trust is the basic foundation for all successful relationships," she claims, "especially when it comes to sex. Most issues within a relationship that could result in cheating can be traced back to a lack of trust.

"Most usually one partner doesn't trust the other to be faithful and decides what's good for the goose can also be good for the gander. Alternatively one partner can feel so untrusted by another, who is constantly accusing them of infidelity, that they decide they may as well get on with what they're always being accused of. This is why you should create and foster as much trust as possible."

Communication keeps you faithful

According to Simon and Alison Watson, who have been married for ten years and run workshops on staying faithful, the best way to foster trust and keep your sex life healthy is through communication. "The more you keep the lines of communication open with your partner, the less reasons they'll have for mistrusting you," Alison explains.

"Another reason that one partner might have for straying," Simon continues, "is that they have certain needs, either emotional or sexual that they feel the relationship is not meeting. If they don't think their current partner will meet those needs they may look elsewhere. The more you talk to each other the more you can monitor the health of your relationship and avoid any pitfalls."

One of the major needs that can often get overlooked, is the way you make your partner feel about themselves.

"Self esteem is often one of the most neglected areas in a long term relationship," Diane says. "But if we start taking our partner for granted they may be susceptible to flattery from someone else, particularly if they're not getting the attention they need at home. The fact that someone finds us attractive is a big factor in our attraction to them. So make certain your partner always knows just how sexy you find them and how much they turn you on."

Experiment and stay excited

"It doesn't hurt to experiment either," Alison notes. "Boredom and the need for variety is another big feature in the reasons why people are unfaithful. Rather than trying new partners, you can always shake up your sex life. "You don't have to start experimenting wildly, but if you add a few new tricks to your existing repertoire you can keep the passion and interest you have in each other alive much longer.

Make sure you're both comfortable with what ever you want to try though. Don't pressure your partner into anything they aren't certain about, but do be responsive to all their needs. Which is all about good communication again."

Updated: 27/05/2009

Written by Jaspre Bark