Adultery

Adultery is generally defined as consensual sexual intercourse by a married person with someone other than their lawful spouse.

Adultery is a common ground for divorce in England and US because, like unreasonable behavior, it offers "instant" divorce where it applies whereas the other three grounds for divorce involve compulsory long delays. Naturally, adultery is only relevant as a ground for divorce where that has actually taken place. If there has been no adultery then the only other ground for "instant" divorce is unreasonable behavior.

The person who has committed the adultery is not able to obtain a divorce on that ground unless his spouse is also guilty of adultery. This can sometimes cause significant problems. For instance, the person who has committed the adultery may well want to obtain a divorce and remarry but his/her spouse may refuse to grant a divorce on the grounds of the adultery. The usual answer to this is, "Well, you can either divorce me on the grounds of my adultery or I will divorce you on the grounds of your unreasonable behavior." This may be problematic if there has been no unreasonable behavior but the threat is often enough to resolve the impasse.

A person who intends petitioning for divorce on this ground must do so within six months of becoming aware of the adultery (which is not the same as within six months of it taking place) otherwise he/she is taken to have "condoned" it. This is rather a quaint word but the reality is that many marriages can survive adultery and the law merely recognizes the fact.

The punishment of adultery, in the United States, generally, is fine and imprisonment. This shows how important is adultery because it harms the marriage so the society itself.