Bigamy vs. Polygamy

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There are different forms of marriage. In contrast to the common practice of only two partners marrying one another, societies exist whose members toe a different path.  One of such forms is bigamy. Bigamy is defined as the act of going through a marriage ceremony with one person while legally married to another.

Polygamy is having more than one spouse at a time, so one must engage in bigamy to experience polygamy.

This guide will explore two notable non-traditional systems of romantic partnership. The similarities, differences, and other related practices between bigamy and polygamy will also be examined.

What Is Bigamy?

Bigamy refers to a marriage between two people, where one-half of the couple is already in an existing marriage.

Bigamy can be intentional and consensual, with one spouse marrying a second spouse knowing that their initial marriage remains legally binding and with all parties consenting. It can also be intentional and not completely consensual, where two or more spouses may not be aware of each other.

It can also be unintentional, as the result of an attempted divorce that was never legally finalized. Bigamy is widely illegal, with all parts of the United States outlawing the practice.

People that are in bigamous unions are viewed as committing crimes. In some areas, simply cohabiting in circumstances that support bigamy can be punished.

What Is Polygamy?

Polygamy is the general union of three or more people into marriage is known as polygamy. For most people, this marriage is believed to be reserved for a man and multiple wives. This is, however, not always the case. Polygamy is a general description for a marriage carried out by any gender with multiple partners.

The types of polygamy are polygyny, polyandry, and group marriage.


When a man is able to marry multiple women at the same time, it is known as polygyny. This marriage is not a popular choice in most societies. However, it may be observed in areas that have experienced a boost in the birth of girls. These societies may have experienced war limiting the number of men available to women. Polygyny is usually essential for the survival of these societies.

A man capable of partnering with multiple women is usually considered wealthy. This is because he must have the means to care for them all. 

This system of marriage is practiced in societies in Subsaharan Africa, such as Mali. It is also observed in certain parts of South America such as the Tsimane of Bolivia.

Forms of Polygyny

Here are the different types of polygyny:

  • Sororal Polygyny: The man takes sisters of a family as wives.
  • Nonsororal Polygyny: In this case, the man selects wives that have no relation to one another. 

What Is Polyandry?

Polyandry is a marriage practice where one woman has more than one husband at a time. Polyandry is observed in very limited communities. However, in societies where this is practiced, it is usually because there is a shortage of women to men. 

Forms of Polyandry

In a setting where a woman marries more than one man at a time, it is usually with either of two different sets of spouses:

  • Fraternal Partners: In this form of marriage, the union is usually between a woman and a set of sibling brothers. 
  • Nonfraternal Spouses: Here, women may instead marry a set of unrelated men for husbands. 

The Mosuo people in China are a matrilineal society known to practice matrilineal polyandry, where men and women are free to have multiple partners and to begin or end relationships as they please.

Women in Polygamous Unions Report Poorer Mental Health

While polygamous marriages may be viewed as unions of necessity in some areas, the women in this marriage usually report higher levels of dissatisfaction with life. These women also report more mental health issues in comparison to their monogamous counterparts.

Group Marriage

Group marriage is also a form of polygamy. This is an arrangement in which all parties involved engage in a marriage-like agreement.

Major Differences Between Bigamy and Polygamy

A union involving multiple partners may be a running theme in bigamy and polygamous unions. However, these relationships are not identical. To distinguish either union from the other, the following should be noted:

Level of Awareness for the Spouses

In typical fashion, spouses of polygamous unions are usually aware of the existence of the other partners. With bigamy, however, one or both parties often remain or are kept oblivious to their partner's other marriage.

Different Classifications in the Law

In some countries, polygamous marriages to multiple partners are considered legal. This is, however, not the case with bigamy, as the ceremony joining one person to multiple people is largely viewed as illegal.

Style of Living 

A bigamist will typically maintain two households to accomodate the separate partners. In contrast, polygamists may keep one household with all spouses present.

The Influence of Religion

Polygamy may be observed as the custom of an area. In other instances, it may receive religious backing. Bigamy may not receive cultural backing, nor is it recognized in religions.

In examining similarities, both practices involve a person married to multiple partners at the same time. Bigamy is required to practice polygamy.

Other Similar Marriage Arrangements

Like bigamy and polygamy, other setups exist that deviate from widely normalized monogamous relationships.

These include the following:

Group Marriages

A group marriage takes place where several males and several females are joined together as husbands and wives. This form of marriage is very rare, and may be observed for economic reasons supported by the partners. 

Open Marriage

In an open marriage, the partners agree to have sexual relationships with people outside of their union. These extramarital relationships are not considered cheating, as they are engaged in with mutual knowledge and consent.

Polyamorous Relationships

A polyamorous relationship recognizes that monogamy is only one of the ways romantic relationships may be forged. This relationship type accepts the possibility of loving more than one person at a given time. It is recognized as a non-possessive form of love, where all involved are aware that multiple partners exist in the union.

Polyamorous relationships come in many different forms, including but not limited to: hierarchical poly, anchor partners, triad, quad, polyfidelity, vee, kitchen table polyamory, solo polyamory, polycule, and more.

5 Sources
Verywell Mind uses only high-quality sources, including peer-reviewed studies, to support the facts within our articles. Read our editorial process to learn more about how we fact-check and keep our content accurate, reliable, and trustworthy.
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By Elizabeth Plumptre
Elizabeth is a freelance health and wellness writer. She helps brands craft factual, yet relatable content that resonates with diverse audiences.