Monogamy is an agreement between two people to be romantically and sexually exclusive. We often think of it as one agreement, but its actually two agreements. One about sex and one about romance.

Monogamy doesn't mean attractions and desires cease to exist. In fact, it exists because people want romantic and sexual exclusivity from their partner in spite of attractions and crushes that may develop on either side.

People desire monogamy for many different reasons that are personal, cultural or religious. So people who have agreed to monogamy still may feel sexual and romantic feelings for others, but they agree not to act on them. This is familiar and pretty easy to understand. What is more complicated is that peoples desire for monogamy may change over time. Just as our preferences for work, leisure, what kind of house to live in and other preferences change. People may be married and monogamous for 20 years and then decide they don't desire monogamy any longer.

Once you leave the realm of monogamy and venture into non-monogamy, its helpful to view things in two subsets rather than just a binary of monogamous or not monogamous. Because monogamy is a two part agreement.

These two parts are: * Sexual exclusivity - partners are not free to act on sexual attractions to others even if they feel them * Romanic exclusivity - partners are not free to build romantic relationships with others even if they feel romantic attraction.

Most flavors of non-monogamy that are mutually agreed upon (called ethical non-monogamy) include romantic exclusivity and sexual non-exclusivity. Its more common now, but that may change.

Sexually non-exclusive; romantically exclusive

For example in swinging, partners have sex with others as a team (sexual non-exclusivity) but don't form romantic relationships with others even though they may feel romantic attraction (romantic exclusivity).

In many open relationships partners are free to have sex with others separately (sexual non-exclusivity), but are not free to build romantic relationships with others even if they have romantic feelings for their sex partners or platonic friends (romantic exclusivity).

Some people don't want sex or don't desire sex without romance. This style rarely works for those kind of folks. Some folks are unwilling to not act on romantic feelings for sexual partners. This style doesn't work for them either.

Sexually and romantically non-exclusive

In polyamory, all partners are free to have sexual and romantic relationships with others. Its a subtype of non-monogamy that allows non-exclusivity in both realms. However, just because someone practices polyamory, doesn't mean they build a romantic relationship with all their sexual partners.

Many people have sex prior to falling in love and the love part just doesn't always happen. Love isn't a guaranteed outcome of sex. Alternatively, many people like to have casual/sexual only partners and decline to build romantic relationships with some sexual partners due to time and energy constraints, preferences, or incompatibity for a romantic relationship.

Sexually exclusive; romantically non-exclusive

Sometimes people ask about sexual exclusivity and romantic non-exclusivity. So the freedom to have romantic relationships with many partners while staying sexually exclusive with one partner. This is rarely workable. Most people who desire sex will want sexual intimacy with their romantic partners. This style doesn't work for people who have a strong desire to connect sexually with romantic partners or who value bodily autonomy and want to be free to connect sexually with romantic partners.

You may ask....what about asexual people? Asexual people do often pursue multiple romantic partners while having no or rare sexual intimacy with them. This is a type of polyamory because it includes the freedom to have multiple romantic partners which is the defining characteristic of polyamory.

But because asexuality is a spectrum, some asexual people will sometimes want to engage in some kinds of sexual intimacy with their romantic partners (everyone is different). So it rarely makes sense for them to offer sexual exclusivity to just one partner. So those relationships are typically romantically and sexually non-exclusive, but may include little to no sex even though the option is there. Just because you can be sexual with multiple people, doesn't mean you will want to....but you might.