Sexual intercourse has traditionally been considered an essential part of a marriage, with many religious customs requiring consummation of the marriage and citing marriage as the most appropriate union for sexual reproduction (procreation). In such cases, a failure for any reason to consummate the marriage would be considered a ground for annulment (which does not require a divorce process). Sexual relations between marriage partners have been a “marital right” in various societies and religions, both historically and in modern times, especially with regard to a husband’s rights to his wife.Until the late 20th century, there was usually a marital exemption in rape laws which precluded a husband from being prosecuted under the rape law for forced sex with his wife. Author Oshisanya, ‘lai Oshitokunbo stated, “As the legal status of women has changed, the concept of a married man’s or woman’s marital right to sexual intercourse has become less widely held.
Adultery (engaging in sexual intercourse with someone other than one’s spouse) has been, and remains, a criminal offense in some jurisdictions. Sexual intercourse between unmarried partners and cohabitation of an unmarried couple are also illegal in some jurisdictions. Conversely, in other countries, marriage is not required, socially or legally, in order to have sexual intercourse or to procreate (for example, the majority of births are outside of marriage in countries such as Iceland, Norway, Sweden, Denmark, Bulgaria, Estonia, Slovenia, France, Belgium)
With regard to divorce laws, the refusal to engage in sexual intercourse with one’s spouse may give rise to a grounds for divorce, which may be listed under “grounds of abandonment”. Concerning no-fault divorce jurisdictions, author James G. Dwyer stated that no-fault divorce laws “have made it much easier for a woman to exit a marital relationship, and wives have obtained greater control over their bodies while in a marriage” because of legislative and judicial changes regarding the concept of a marital exemption when a man rapes his wife.
There are various legal positions regarding the definition and legality of sexual intercourse between persons of the same sex or gender. For example, in the 2003 New Hampshire Supreme Court case Blanchflower v. Blanchflower, it was held that female same-sex sexual relations, and same-sex sexual practices in general, did not constitute sexual intercourse, based on a 1961 definition from Webster’s Third New International Dictionary that defines sexual intercourse as coitus; and thereby an accused wife in a divorce case was found not guilty of adultery. Some countries consider same-sex sexual behavior an offense punishable by imprisonment or execution; this is the case, for example, in Islamic countries, including LGBT issues in Iran.
Opposition to same-sex marriage is largely based on the belief that sexual intercourse and sexual orientation should be of a heterosexual nature. The recognition of such marriages is a civil rights, political, social, moral and religious issue in many nations, and the conflicts arise over whether same-sex couples should be allowed to enter into marriage, be required to use a different status (such as a civil union, which either grant equal rights as marriage or limited rights in comparison to marriage), or not have any such rights. A related issue is whether the term marriage should be applied.