Bigamy in the context of "Bertrade of Montfort"

Extramarital sex is sexual activity in which at least one sex partner is a married person and the partners are not married to each other. The term may be distinguished from premarital sex where neither partner is married.

Where extramarital sex does not breach a sexual norm, it may be referred to as consensual non-monogamy (see also polyamory). Where extramarital sex does breach a sexual norm, it may be referred to as adultery or non-monogamy (sexual acts between a married person and a person other than the legal spouse), fornication, bigamy, philandering, or infidelity. These varying terms imply both immoral or religious consequences, charged whether via civil law or religious law.

Tiberius Claudius Caesar Britannicus (12 February AD 41 – 11 February AD 55), usually called Britannicus, was the son of Roman Emperor Claudius and his third wife, Valeria Messalina. For a time, he was considered his father's heir, but that changed after his mother's downfall in 48, when it was revealed she had engaged in a bigamous marriage without Claudius' knowledge. The next year, his father married Agrippina the Younger, Claudius' fourth and final marriage. Their marriage was followed by the adoption of Agrippina's son, Lucius Domitius Ahenobarbus, whose name became Nero as a result. His stepbrother would later be married to Britannicus' sister Octavia and soon eclipsed him as Claudius' heir. After his father's death in October 54, Nero became emperor. The sudden death of Britannicus shortly before his fourteenth birthday is reported by all extant sources as being the result of poisoning on Nero's orders; as Claudius' biological son, he represented a threat to Nero's claim to the throne. In Suetonius' The Twelve Caesars, he claims that Nero poisoned Britannicus out of envy of his voice, due to Nero's own obsession with performance and being the best entertainer of all time (as suggested by him wanting the games he hosted to be described as "the greatest ever undertaken").

A husband is a man involved in a marital relationship, commonly referred to as a spouse. The specific rights, responsibilities, and societal status attributed to a husband can vary significantly across different cultures and historical periods, reflecting a global perspective on this role.

In many parts of the world, heterosexual monogamous marriage is the prevailing norm, where a husband and wife form the basic unit of a family. Legal systems in numerous countries enforce monogamy and prohibit bigamy and polygamy. Traditionally, husbands often held the position of being the head of the household and the primary provider, a role that was often considered paternalistic. However, the evolving dynamics of modern society have led to a shift in these roles. Today, a husband is not automatically designated as the sole breadwinner, especially when his spouse pursues a more financially rewarding career. This change reflects a global trend in the changing dynamics of gender roles and family structures.

Polygamy (from Late Greek πολυγαμία polygamía, "state of marriage to many spouses") is the practice of marrying multiple spouses. When a man is married to more than one wife at the same time, it is called polygyny. When a woman is married to more than one husband at the same time, it is called polyandry. In contrast, in sociobiology and zoology, researchers use "polygamy" more broadly to refer to any form of multiple mating.

In contrast to polygamy, monogamy is marriage consisting of only two parties. Like "monogamy", the term "polygamy" is often used in a de facto sense, applied regardless of whether a state recognizes the relationship. In many countries, the law only recognises monogamous marriages (a person can only have one spouse, and bigamy is illegal), but adultery is not illegal, leading to a situation of de facto polygamy being allowed without legal recognition for non-official "spouses".

A parish register, alternatively known as a parochial register, is a handwritten volume, normally kept in the parish church of an ecclesiastical parish in which certain details of religious ceremonies marking major events such as baptisms (together with the dates and often names of the parents), marriages (with the names of both partners), and burials (within the parish) are recorded. Along with these events, church goods, the parish's business, and notes on various happenings in the parish may also be recorded. These records exist in England because they were required by law and for the purpose of preventing bigamy and consanguineous marriage.

The information recorded in registers was also considered significant for secular governments’ own recordkeeping, resulting in the churches supplying the state with copies of all parish register entries. A good register permits the family structure of the community to be reconstituted as far back as the sixteenth century. Thus, these records can be distilled for the definitive study of the history of several nations’ populations. They also provide insight into the lives and interrelationships of parishioners. Historically, a parish's churchwarden was responsible for certifying the parish register and submitting it alongside the churchwarden's accounts for annual examination by the bishop.

Morganatic marriage, sometimes called a left-handed marriage, is a marriage between people of unequal social rank, which in the context of royalty or other inherited title prevents the principal's position or privileges being passed to the spouse or to any children born of the marriage. The concept is most prevalent in German-speaking territories and countries most influenced by the customs of the German-speaking realms.

Generally, this is a marriage between a man of high birth (such as from a reigning, deposed or mediatised dynasty) and a woman of lesser status (such as a daughter of a low-ranked noble family or a commoner). Usually, neither the bride nor any children of the marriage has a claim on the husband's succession rights, titles, precedence, or entailed property. The children are considered legitimate for all other purposes and the prohibition against bigamy applies. In some countries, a woman could also marry a man of lower rank morganatically.

Rachel Jackson (née Donelson; June 15, 1767 – December 22, 1828) was the wife of Andrew Jackson, the seventh president of the United States. She lived with him at their home at the Hermitage, where she died just days after his election and before his inauguration in 1829—therefore she never served as first lady, a role assumed by her niece, Emily Donelson.

Rachel Jackson was married at first to Lewis Robards in Nashville. In about 1791, she eloped with Andrew Jackson, believing that Robards had secured the couple a divorce. It was later revealed that he had not, meaning that her marriage to Jackson was bigamous. They were forced to remarry in 1794 after the divorce had been finalized.