Adultery is a voluntary consensual relationship between a married individual and someone who is not his/her lawful spouse. Adultery is considered as legally wrong and is a punishable offense. The act of adultery is a crime which breaches the marriage vows and is detrimental to public morals. It is regarded as illegal in some countries and certain laws have been passed to keep a check over adultery. Although adultery is not a criminal offense, it may have legal consequences and the individual concerned may be penalized and punished especially if the case is pertaining to divorce.
Section 497 A of IPC
Whoever has sexual intercourse with a person who is and whom he knows or has reason to believe to be the wife of another man, without the consent or connivance of that man, such sexual intercourse not amounting to the offence of rape, is guilty of the offence of adultery, and shall be punished with imprisonment of either description for a term which may extend to five years, or with fine, or with both. In such case, the wife shall not be punishable as an abettor.
Hindu Marriage Act, 1955, Section 13(1)(i) describe Adultery as a ground of divorce.