03/10/2013 10:32 BST | Updated 23/01/2014 18:58 GMT

10 Things You Need to Know Before You Accuse Your Partner of Cheating

• Sometimes there is another, legitimate, explanation for a person losing ten pounds, working late and losing interest in sex. I just don't know it.

• You need proof, but cheats guard their mobiles with their lives and they never get itemised bills. If the inbox on their phone and email are clean, look for separate folders with particularly unappealing titles such as "Finances" or "Work"

• If you go looking for dirt, don't be surprised when you find it. James Myers of Metropolitan Investigations says that "by the time a person hires a private detective they know their partner is having an affair, they just need to prove it." Surveillance costs £40 per hour and the average spend is between £500 ad £1,500.

• Why do men cheat cheat? M Gary Neuman, author of 'The Truth About Cheating: Why Men Stray and What You Can Do To Prevent It', says that only 8% of men blame sexual dissatisfaction at home, whereas 48% of men say they feel under-appreciated by their wife.

• Mind you, men are also more likely than women to justify their extramarital sex, and they experience less guilt when they engage in it. (Johnson, 1970; Athanasiou et al., 1970; Spanier & Margolis, 1983).

• Figures on the prevalence of marital infidelity vary, but its not as common as you might think. The Sex in America study estimates that 25% of married men and 15% of married women have engaged in extra martial sex (Laumann, 1998) and those figures are closely echoed in Danish Studies and The Natal study in the UK. However other research estimates that over the course of a marriage, 30 to 60% of men and 20 to 50% of women will have an affair (Glass & Wright, 1992, Petersen, 1983).

• Why do women cheat? General dissatisfaction with their marriage and revenge against a cheating husband (Glass & Wright, 1992).

• But women whose husbands have affairs are more willing to forgive their partner than men whose wives have affairs (Lawson, 1988).

• Even so, extramarital sex is the most cited cause of divorce cross-culturally (Betzig, 1989).

• Is reconciliation an option? Only if your partner is wiling to end the affair immediately. If both of you can commit to improving your relationship and you can diffuse your anger and hurt enough not to keep hauling your partner over the coals, counselling may help. Contact The Tavistock Centre or RELATE.