UNFAITHFUL women beware. Chances are your male partner is on your case. In fact, he is likely to suspect infidelities even when you have kept to the straight and narrow. The flip side is that to counter this constant vigilance, women may be better than men at concealing illicit liaisons.

Paul Andrews at Virginia Commonwealth University in Richmond and colleagues gave 203 young heterosexual couples confidential questionnaires asking them whether they had ever strayed, and whether they suspected or knew their partner had strayed. In this, 29 per cent of men said they had cheated, compared with 18.5 per cent …