Monogamous

Monogamy or Monoamory is describes an exclusive relationship between exactly two people. Monogamous can be used both as a description of a relationship with exactly two people and as description of people who desire such relationships. Ideally, both participants in a monogamous relationship only have a single partner at a time, and it is not an open relationship. Monogamous people can still be attracted to multiple people at once, however they would not want to be in a relationship with both of those people at the same time.

The term monogamous is commonly used by polyamorous people to describe relationships with only two people and people who are not polyamorous.

Monogamy vs. Monoamory
Under the most strict definition of the term, monogamy refers to being married to a single person at a time, while monoamory refers to being in a relationship with a single person at a time. However, the term monogamy has come to be used as in a more broad sense and can be used regardless of whether the people involved are married.

History
Monogamy has occured amongst history and nature for thousands of years. Monogamy, despite being shown in media more often, is just as common as non-monogamy in culture and nature. Many creatures in nature take monogamous routes, while many other take polyamorous/polygamous routes, or take both routes depending on the species.

Psychology has shown that niether monogamy or polyamory are "better" for society, as personal preferences and emotional structures of individuals lead one to needing different forms of relationships.

Flags
The original monogamous flag was coined by Tumblr user pride-flags-for-cishets on August 19th of 2016. It has no confirmed meaning. The second flag was coined by Reddit user u/Orion1626 on August 21st of 2020. It also has no confirmed meaning.

Resources

 * 1) https://pride-flags-for-cishets.tumblr.com/post/149195445851/monogamy-pride-flags
 * 2) https://www.pinterest.com/pin/151292868718586902/
 * 3) https://www.betterhelp.com/advice/monogamy/everything-you-need-to-know-about-monogamy-vs-polygamy/
 * 4) https://en.wikipedia.org/wiki/Monogamy
 * 5) https://www.reddit.com/r/QueerVexillology/comments/idu3cc/new_monoamoury_and_polymonflux_flags/