They will be forced into a corner from which they will not be able to get out. If they have been active outside the marriage, their is the fear of being found out that: They have been unfaithful (men or women). They may have exposed their wives to possible health risks through sexually transmitted diseases. They may have had contact with people who are potentially a threat to their wife and family (e.g. unscrupulous men who are using them to get to their children).
Smoking gun ...... Even with apparently a "smoking gun" in their hand, men are capable of denying all knowledge, proclaiming their innocence, and will continue to do so, even when conclusive evidence is presented to them, such as compromising photographs, e-mails, records of sites visited on the internet, discussion groups, dating and so on. If they cannot find a reason for denial, they will try to put the blame elsewhere or refuse to talk about it altogether.
When we come to think about it, is this any different to the way politicians behave when forced into a corner? Is it therefore surprising that people can behave in this way? The frustration for wives and girlfriends is finding ways of unlocking the door, getting to the truth and then working out what to do next: Accept what has happened and move on inside the relationship move on outside the relationship. Find some sort of closure. "They can lie all they like but in her heart 'n' soul a woman knows......"