The whole premise of Married at First Sight is to help those who have been unlucky in love find a suitable spouse, based on scientific knowledge of relationships.

But what about people who don't want a partner? And those who are attracted to multiple genders? Or those people who are in a relationship with more than one person (consensually, rather than in an affair)?

Most of us tend to have pretty rigid ideas about what is "normal" in romantic relationships and sexual preference.

But contemporary research and theorising indicates humans are able to be much more flexible when it comes to sexuality and relationships. That is, we are quite sexually and rationally fluid.


What does this mean?

Sexual fluidity refers to the notion that our sexuality, sexual orientation, or sexual preferences are not as fixed as we think. We live in a predominantly heterosexual society. And this is seen as normal, biological and inevitable. But in reality, sexuality and its expression is much more fluid than we realise, and socially and cultural mediated.

Historically, for example, same-sex sexual behaviour was pervasive - but it was called different things and understood in different ways. In ancient Greece, it was acceptable for older men to have sexual relations with younger teenage boys without it implying homosexuality. There are detailed histories from the Victorian era of "passionate female friendships", where women were lovers, but did not identify as lesbian.

During the early 20th century (in New York City), young well built and attractive working class men named "hustlers" would have sex with older gay men for monetary "upkeep". These men still held on to their identity as heterosexual and dated and married women.

We know that human sexuality is much more fluid than we realise. Even 70 years ago, one of the most famous sexologists, Alfred Kinsey, posited that our sexuality falls on a seven-point continuum:

1. Exclusively heterosexual
2. Predominantly heterosexual (only incidentally homosexual)
3. Predominantly heterosexual (but more than incidentally homosexual)
4. Equally heterosexual and homosexual,
5. Predominantly homosexual (but more than incidentally heterosexual),
6. Predominantly homosexual (only incidentally heterosexual),
7. Exclusively homosexual.

Later, an extra category labelled X was added to indicate asexuality (to capture those who do not experience sexual attraction to anyone).

Kinsey was not some sexual radical or "free love"-espousing hippy. He was a biologist and man of science who interviewed 5300 men and 6000 women over 25 years across the US, before he came to these conclusions.

What he realised was that although the moral order of the time disparaged non-heterosexual contact and relationships, people had hidden desires for the same sex as well as closeted same-sex interactions, but did not necessarily identify as gay or lesbian.

Historically, sexual acts have not necessarily defined identities as they do today.

And although many researchers still used behaviour to measure sexuality - even up to the turn of this century - this has radically changed.

Cutting-edge work today indicates it's not whom you sleep with (your sexual behaviour), or even whom you find sexually and romantically attractive (your desire), but how you choose to identity yourself that determines your "sexual orientation".

For example, you might be a man attracted to women and men who has only had relationships with women - yet you still identify as bisexual. Or you might identify as "queer" - a catch-all term that basically means: whatever I am, I'm not heterosexual.

Some go further and call themselves queer as a political statement against sexual labels.

There is now an array of sexual and relational possibilities and people have developed new language and terms to reflect the blossoming of these understandings.

We now have categories such as Polysexual (attracted to multiple genders/gender identities), Skoliosexual (someone who is attracted to genderqueer or non-binary people), and Pansexual/Omnisexual (attraction to someone regardless of their gender).

Some very niche categories are also out there, including: Objectumsexual (someone sexually attracted to inanimate objects), Gynesexual (sexual attraction towards women or those with feminine characteristics), Androsexual (sexual attraction towards men or those with masculine characteristics), and, finally, Androgynosexual (being sexually attracted to both men and women, specifically to those with androgynous appearances).

In relationships, although there are many non-monogamous options, such as polyamory (which takes on many structures and can include open relationships) and those who opt out of relationships, the duo (more precisely, the hetero duo) still heavily dominates.

Maybe one day we will have a Married at First Sight where heterosexual marriage is the minority and there is a polyamorous wedding among a pansexual, gender-fluid and skoliosexual trio.

I know I'd watch that.

Each week, MAFS expert Dr Pani Farvid analyses an aspect of the show.