There's something odd about the couples I hang out with – and probably the ones you hang out with, too. Psychologists, sociologists and economists have noticed it. Geneticists and anthropologists too.

Take a dinner I went to a while back, where I chatted with a university researcher couple, a designer couple and a lawyer couple who both worked in the same government department.

At work, I'm surrounded by journalist couples – so many that I decided years ago that it was wisest to just assume that every journo is married or dating someone in the newsroom (and if not this newsroom, then a newsroom somewhere in the city).

Lin (not her real name) and her husband are architects. They like the same kinds of films, are both passionate about art and other creative pursuits, share the same social and political values, and have a similar sense of humour.

Most of the time, their similarity is an advantage – except maybe when they go to a restaurant, Lin says. "We always want to order the same thing on the menu, so have to negotiate who gets it."

The biggest difference between them might be their heights: Lin just scrapes past 150cm while her husband is nudging 2 metres. "It works though because it means he can reach all the things that are high up," she says.

Studies have found that the tendency for partners to resemble one another goes far beyond the demographic factors that might logically bring them together. Romantic partners also tend to align on traits as diverse as psychiatric disorders, disease and substance use, sociability and moodiness, body shape, height and whether you were breastfed as a baby or both wear glasses.

We're working on a project about why we choose the partners we do, and we want to hear your stories.

In a society that is more culturally and ethnically diverse than ever, with greater social mobility, expanded travel and a dizzying array of dating apps to introduce us to a wider variety of potential partners than our grandparents care to imagine, are our partnerships becoming more diverse?

In other words, when it comes to modern love, do opposites attract or does like attract like?

For Ali and her partner, it's definitely a case of opposites attract. "They eat meat and I'm vegetarian. They're a scientist; I'm an artist. They're much smarter than me and have much more patience and time for strangers than I do. I like to go out many nights a week … They don't like to go out much at all and will last-minute cancel, even if we have tickets, because they want to stay home in bed," Ali says.

"I helped them move house. Their whole life fit in one minivan! My stuff might fit in like, 12 vans, not including my plants. They didn't own any pot plants, which freaked me out … My plants alone would add another four van-loads, probably. 

"Oh, and we have totally different ways of expressing love! I spend hundreds and spoil them on birthdays, Christmas or just whenever. I've not gotten even one present off them yet," Ali laughs.

She then concedes: "But they're much better at saying they love me."

These differences have become strengths for the pair, who communicate well, don't judge one another and share core values about living in a compassionate world.

"If you're too similar to each other, I think there's not as much room for growth and challenge, or interesting new experiences," Ali says.

Pete and his wife know a thing or two about navigating new experiences. Nina (not her real name) fled her home in Syria during the civil war and arrived in Australia as a refugee about a decade ago.

"Culturally we're very different … I'm a mix of Scottish, Irish and Welsh — basically, Whitey McWhiteface. She's Assyrian and has a very strong cultural and religious identity," Pete says.

"Where she lived, ISIS was literally playing music down the street saying, 'We're going to rape and pillage you, and cut the power,' and all that … My idea of adversity is working in the local video store and putting up with the weird customers that used to come in," he jokes.

But the chemistry between the pair was instant and their love has bridged differences in culture, religion, ethnicity and language.

"I had only ever dated people from my culture and background. I never expected [this]," Nina says.

"But Pete doesn't live in a bubble. He's travelled a lot, he's keen to learn and very supportive of my culture, which makes a lot of difference.

"I always thought values come from culture but I started to see that you can share the same values but be from different cultures."

Tell us your love stories

Do people often remark on how similar you are to your partner? Do you dress the same, crack the same jokes and finish each others' sentences? Have strangers mistaken you for siblings?

Or perhaps you're a classic example of opposites attract. Are you doing yoga on a hilltop at sunrise, leaving your partner to sleep happily until midday? Do you meticulously arrange your bookshelves according to subject, height and ease of access, while your partner uses the bedroom floor as their wardrobe?

Or maybe you're not in a relationship right now, but you know a thing or two about being with someone either very similar or very different to yourself.

There are more than 5 million couples in Australia (and millions of exes). We want to hear from you.

Your anecdotes will be published in a series of ABC News stories later this year. Ideally, you'll also send a photo of yourself or you and your partner (if you're still together!).

We will publish your name, age and location alongside your story unless you tell us not to.

And if you don't want to fill in this form and would prefer to speak to a reporter in confidence, please email: ting.inga@abc.net.au