Nothing is more sacred than the sanctity of marriage. Especially when it is bound by law to honor and cherish a commitment. But temptation can often lead people astray, which in turn leads to adultery. So is adultery illegal? Adultery is considered a sin, and even referred to specifically in the Bible. It has been punishable with stoning, flogging, public humiliation, and even execution. Adultery is an extramarital affair usually pursued due to dissatisfaction with a spouse. It has mostly been one-sided, with the laws favoring men and treating them with a lighter sentence, while women were treated much more harshly, with some countries even giving society permission to take the law into their own hands. This is evident even today in the form of honor killings. But with open relationships and same-sex relationships being accepted far more openly now than they were before, the question arises - should the government be allowed to invade the choices made by consenting adults in their privacy? The United States of America inherited its laws from the British monarch, and these were enforced to protect marriage. Although the American Law Institute removed adultery from its Model Penal Code, many states still prohibit adultery, but the laws are rarely enforced. The Uniform Code of Military Justice still considers adultery to be illegal. The US Army bars servicemen from having extramarital affairs, but doesn't prosecute those involved unless it harms order and discipline. But a complaint may result in the court martial of the officer involved, and subsequent removal if convicted. Adultery laws were made to prevent the birth of illegitimate children, prevent the transfer of sexually transmitted diseases (STDs), as well as protect marriages. The laws enforced in the US states have been outlined here. New York: It defines an adulterer as someone who engages in sexual intercourse with someone other than his legal spouse, and is considered a class B misdemeanor. North Carolina: It defines adultery between two people who lasciviously and lewdly associate, bed, and cohabit together. Those pursuing a lawsuit must file it within 3 years from the last act of adultery, which constitutes a ground for divorce. Minnesota: If a married woman has sexual relations with someone other than her husband, then both are guilty of adultery, which is a misdemeanor. They may be sentenced to a year of imprisonment, or fined $3,000. Michigan: Adultery is illegal, but can only be punished upon a complaint by the affected husband or wife. When a married man sleeps with an unmarried woman, only he's guilty. On the other hand, if a married woman sleeps with an unmarried man, they both are guilty. It is considered a felony, and punishable with up to 4 years of imprisonment, or a $5,000 fine, or both. Arizona: Adultery is defined as a married person who has sexual intercourse with someone other than his or her spouse, and an unmarried person who has sexual intercourse with a married person who is not his or her spouse. It is a class 3 misdemeanor. Out of the two guilty parties, even if only one of them is married, both are still punished. No prosecution is commenced unless a formal complaint has been registered by the husband or wife. South Carolina: The fine for adultery is up to $500, or imprisonment for a year. Furthermore, divorce laws deny alimony to the adulterous spouse. Adultery is illegal in the states of North Carolina, Rhode Island, Massachusetts, Alabama, Florida, Tennessee, Virginia, Utah, Missouri, Mississippi, Georgia, Indiana, Maryland, Arizona, Michigan, Illinois, Idaho, Kansas, Wisconsin, New York, and South Carolina. It's still considered a misdemeanor in these states.

▶	In recent years, the states of New Hampshire, Colorado, and West Virginia repealed their adultery laws, and made it legal.
▶	The states of Texas, Connecticut, Alaska, Arkansas, Iowa, Kentucky, Nebraska, Nevada, New Jersey, Oklahoma, Oregon, Vermont, and California are no-fault states, where the courts do not consider adultery as illegal before granting a divorce.
▶	The states of Delaware, Louisiana, Montana, North Dakota, Ohio, Pennsylvania, and Wyoming allow fault-based divorces based on adultery. Maine is the only state that offers a compromise between fault- and no-fault-based divorces.
▶	The states of Hawaii, New Mexico, South Dakota, and Utah allow the possibility of alienation of affection as damage caused by a third party to be responsible for the failure of a marriage.

As you can see, the laws are one-sided and mostly favor men, as they were deemed to be the breadwinners of the family, and had the right to choose their heirs. Many argue that the laws regarding adultery are based on an archaic concept of marriage laws, and cannot be unconstitutional if agreed between consenting adults.