Adultery (as referred to in the Bible) is sexual intercourse between a married person and a person other than their spouse (compare [[fornication]]). The Bible forbids adultery in the [[Ten Commandments]] (Exodus 20:14). Legal definitions may vary.
Adultery may ruin trust between husband and wife and break up families. It is contrary to the traditional marriage pronouncement derived from Matthew 19:6: "Wherefore they are no more twain, but one flesh. What therefore God hath joined together, let not man put asunder." It also breaks the promise that the bride and groom make to each other in virtually every form of marriage ceremony observed in the U.S.—even secular observances conducted in judge's chambers, or in vows written by the couple themselves.