Please note this is a work in progress typed from notes that I scribbled at work one day during a coffee break. I am not an expert, merely experienced in discussions on the subject. I acknowledge this is a far more complex and personal topic that can never be summed up in such simple terms, but this is intended to be a reference for me to explain broader concepts and I'm not interested in bending this framework in any direction outside of my own developed understanding.
Sexual and relationship diversity comes from a variety of orientations that people have — that is, personal dispositions regarding their attraction towards people and overall desires for fulfillment in sex and relationships. These are culturally dependent upon how society has framed relationships and sexuality; they are not absolute concepts found across all past and present societies, and they are dependent upon a number of other social institutions regarding family, the individual, and the construct of "human nature" as culturally defined. This framework examines such dispositions on four different components: quantifiers, qualifiers, gendered direction, and aspect. The table below provides a non-exhaustive set of examples:
Quantifiers | Qualifiers | Gendered Direction | Aspect |
mono- | fray- | homo- | -sexual |
poly- | demi- | hetero- | -romantic |
grey- | bi-/pan- | -sensual | |
a- | -aesthetic |
Note that the aspect component comes from the Split Attraction Model (SAM) that acknowledges some people experience different elements of their orientation in different ways, e.g. someone may be asexual but biromantic if they are not sexually attracted to any gender but desire romantic relationships with more than one gender including their own. The SAM is not a universal approach to identification. Many feel no difference or need to separate the "aspect" categories. It is a very personal matter. HOWEVER, allonormativity* (the default assumption that everyone is attracted to other people or desires/seeks out partners) is a systemic bias that disadvantages both non-SAM a- folks (i.e. aromantic asexuals, or aro aces) and anyone of a split orientation (e.g. heteroromantic asexuals, homoromantic pansexuals, etc.). It also oversimplifies and dismisses or stigmatizes poly or queerplatonic relationships.
(*"allo-" is sometimes used as the opposite of "a-" (e.g. allosexual meaning people who aren't asexual), and a less common equivalent is "zed-". Many people in the communities that discuss these differences do not use this language and may just prefer the aspect element, like "sexual" or "romantic" in topical discussions.)
The "poly-" prefix is most often used in reference to polyamory (the inclination to feel romantic or sexual towards multiple people at a time, and/or the practice of holding multiple romantic or sexual partners) or polycules (networks of typically romantic committed relationships connecting multiple partners). This is in contrast to what's mostly called "monogamy" (though the -gamy suffix technically refers to marriage and polyamory is distinctly different from traditional polygamy). "Monoamory" is a more fitting comparable term. This refers to feeling romantic towards or desiring a romantic relationship with one person at a time. It is currently the dominant cultural practice, so not everyone engaging in it may intrinsically be monoamorous; for this reason, "monoamory" and "polyamory" can sometimes refer solely to the practice, even when the intrinsic orientation of the individual may be different from their current circumstances.
There are further ways to distinguish one's orientation and define it in specific terms. Some people's pattern of attraction or desire places them in ambiguous territory, most often just outside of "a-" orientations. There is a wide array of terminology, sometimes to degrees of specificity that are irrelevant to all but the individual. There are many coined terms that are not discussed here, as it's needlessly complex for understanding this framework, and the lexicon is ever-evolving. However, some terms have gained traction in expressing sexual and relationship diversity, such as "demi-" (requiring a strong bond before developing these feelings), "fray-" (losing these feelings after getting to know someone), or "grey-" (limited or minimal attraction or intrinsic desire). These can be combined with quantitative and gendered direction of any aspect of attraction, including combinations under the SAM.
Even further from our conventional understanding of sexuality and relationships, some fall outside of what we're taught to recognize as "partner" or "significant other" while still being as important as romantic relationships. Aromantic people may establish a relationship that is called "queerplatonic" — that is, a bond beyond friendship (but not romantic) that includes some life integration as a committed relationship. This could include elements of personal, financial, social, or emotional interdependency. Queerplatonic relationships (QPRs) can also develop into polycules when multiple people are involved, similar to polyamorous romantic relationships.