When a married woman gets into an illicit affair, it is either because she is bored of / unhappy in her marriage or that she has given into temptation.
Its obvious that a husband needs to share most of his attention to his family. Many married men are living on the budget, as he needs to pay for bills, mortgage, childs education, insurance and other family-related expenses. Often, he tries to avoid the crowd and visiting popular places in your town, to avoid meeting his friends, relatives, or worse, his wife. Opportunity is often the single most important reason why many men tend to cheat.
He wont be available for you on Christmas, Easter and even the St. Everyone sometimes enjoys the pleasure of doing something without others knowledge.
For many men, faithfulness is a matter of options and they cheat because they can choose.
It is certainly unwise to categorize every man in the same bracket and you shouldnt expect all men to cheat immediately given the opportunity.
Nevertheless, the situation is certainly very tempting and if an irresistible woman gives even the slightest hint of opportunity, its quite likely for a man to cheat or at least, take a little pleasure for some time.