It has averaged more than a million viewers an episode, hogged the conversation in social media and in offices around the country, and even did the unthinkable, knocking My Kitchen Rules off its perch as most-watched show on almost half of the occasions the two went head-to-head.

Year-on-year, Married is up 16.6 per cent on its metro audience, while MKR is down by more than 20 per cent, though the latter has still averaged more viewers (1,244,000 versus 1,151,000).

Nine's head of content, production and development, Adrian Swift, says the success is down to a deliberate decision to take on what has been the biggest show on television for the past few years.

"We put season two up against My Kitchen Rules last year with no real expectations it would take a chunk out of it, and what we found was it was really good at attracting a younger, female demographic, and taking them out of MKR. As programmers we thought 'that's interesting'."

So they set about retooling and upsizing.

The first season of the show, in 2015, had just four couples and six episodes. Season two had four couples and eight episodes, and season three had five couples - including the first gay pairing on an Australian dating show - and eight episodes (seasons two and three both aired last year).

This season was vastly expanded, with 10 couples and 27 episodes to date, with Sunday's reunion dinner party and Monday's session with the experts still to come.

"We looked at the things that worked - the dinner parties, the weddings themselves, the home visits, getting the relatives and friends to come and comment - and instead of doing them randomly we formalised them," says Swift.

"When we looked at blowing it out, our thinking was two months on their own would be really hard, but coming together at the dinner parties and the commitment ceremonies would give them the ability to see the other participants and measure themselves against them, and give them some sort of support and framework to operate within."

It would provide plenty of drama too, of course. But Swift insists the show took a largely hands-off approach where storylines are concerned.

"It's not a case of constructing the action, it's a case of following the action," he says. "Married is what we call a clockwork mouse show. You create the mouse, which is the premise, the experiment, you wind the mouse up, and you let the mouse go."

Anyone who has paid attention will have noticed that distance has been a major factor this season. Of the 10 starting couples, only one - Cheryl (Gold Coast) and Jonathan (Brisbane) - were from the same state. Once the rebounding Cheryl and Andy (Perth) were paired - after being described, hilariously, as survivors of failed marriages - all the couples faced the distance issue.

So, was it deliberate? Swift says not.

"We said let's try and not put people who are a long way apart together, because that's just going to be a pain in the arse for all concerned, and it makes the show a lot more expensive to make. But when we sat down with the psychs, they said, 'Look, if this is going to be anything approximating a vaguely scientific experiment, we've got to choose from the biggest pool of people. If we've got to choose from people in the same state or the same city, we're not making the best match, we're making the easiest match'."

For season four the show, which is produced by Endemol Shine for Nine, had 10,000 applicants. For next year, they've already had about 14,000 love-seeking exhibitionists apply.

And as for the claim that this is a social experiment founded in relationship "science", exactly how much does he back that?

"I can't tell you it's 46 per cent scientific," he laughs. "But the experts genuinely spend a lot of time with the participants to understand what they want and need, trying to find the fundamental traits that match people, rather than just the superficial ones."

Yes, well. With just one extant relationship from 13 in the show's first three seasons, and maybe three at best this year, you'd have to say it looks more like art (or artifice) than science.

"Well," he concedes, "you wouldn't have it published in Nature."

Karl Quinn is on Facebook at karlquinnjournalist and on Twitter @karlkwin