One reason for divorce: "Cheating". It's estimated that anywhere from 30% to 60% of married men will engage in an extramarital affair. The percentage of wives who will do so is smaller but on the increase.
Some are able to overlook, or forgive, cheating. Marital counseling may help, but much depends on the ability and experience of the counselor. Some cannot forgive cheating and believe a spouse's infidelity must result in a divorce.
Cheating occurs in men because they're wired for "conquest", for "variety". Some dismiss this view. Men and women may also find themselves bored, sexually. Women may be attracted to an affair because it makes them feel wanted, desirable. For men, it's often about sex and feeling virile.
One irrefutable fact is that the majority of prostitutes' clients are married men. Then, too, there are numerous websites devoted to extramarital affairs, and there are thousands, if not tens of thousands of members.
Here are some signs he/she is having an affair.
Whether or not a marriage can survive after infidelity depends largely on the individuals involved. Only you can answer that. But if you discover your spouse has engaged in an extamarital relationship, don't be rash and act too quickly. Before shouting, "That's it! I want a divorce!", take some time to cool down, and maybe see a counselor--perhaps first by yourself then with your spouse. Consider the consequences for you and for your children, if you have children.