As narratives go, “boy meets girl” is as old as the hills. So too is “Boy meets girl, then meets someone else, and then everybody gets upset”.

Certainly, some evolutionary biologists will note that man is hardwired to ratchet up as many sexual partners as he can, in a bid to create as many offspring as possible. Between technology and a relaxing of social mores, marriage as an institution is under threat, despite our attachment to romantic notions of happy-ever-after. But is there an alternative to clandestine encounters and the soul-sapping subterfuge of an affair?

Well, what about “boy meets girl, then meets someone else, and they all live happily ever after”? Monogamy has long been our main expression of love for one another, but a growing number of Irish people have realised that there’s another way.

Polyamory Ireland, a 300-strong group of people who practise the relationship model of having more than one partner at any given time, hold regular meetings in Dublin. Its members range in age from teenagers to grandparents and are multicultural and well-travelled.

“A lot of people think that it’s like a swingers’ party where we all pair up,” says Tim Sinnott, smiling. “The fact is, polyamory can be pretty complicated, and it’s handy to talk to people in a similar situation about it.”

Monogamous relationships aren’t without their complications, certainly, but the fact that three or more people are involved in a poly relationship means that the interpersonal combinations are plentiful. There is a “V” (one person is the “hinge”, and has two lovers who aren’t romantically involved with each other), a “triad” or a “quad” (a relationship between three or four people). A “W” denotes a fivesome in which two lovers have their own separate lovers. Some, not all, have a primary relationship, then secondary or tertiary lovers. With the constraints of monogamy effectively by the wayside, anything is possible.

“The only rule I have with my partners is that we use protection [during sex],” says Sinnott. “But for the most part, we treat it as ‘don’t put rules on each other’. In a lot of monogamous relationships, you just stop talking about your relationship with each other, but in poly you’re expected to talk about it a lot.”

This stands to reason, and it’s something that appears to be common among the polyamorous people I’ve interviewed. Respectful and open communication is integral to the smooth running of any partnership(s). It is not taken for granted that the relationships can live on love alone. Like their monogamous counterparts, polyamorous relationships are committed and honest. Jealousy and possessiveness can occasionally rear its head, but polyamorists tackle the issue with their lovers head-on to find a way around it.

‘I had a poly leaning without realising’

Sinnott fell into his first poly relationship quite by accident two years ago, and it was a revelation for the 28-year-old. Until recently, he was in a

V with two other women; long distance put paid to one of his relationships. “I had a lot of open relationships in the past,” he says. “I had a poly leaning without realising it, and thought that it was just a fear of commitment. I’d be in a relationship and think, I’m going to be unfaithful, so maybe we should break up. So poly was a good fit. But trust me, you don’t automatically become fantastic at it.”

People with no experience of polyamory often wade in with their own opinions on Sinnott’s relationships. “I ended up having a row with someone recently who said, ‘Well, obviously you don’t love those girls. I think what you do is awful.’ When I asked her why, she said, ‘Well, people just don’t do that.’ Guys I know think I’ve cracked the code, so to speak, and see me as a bit of a stud,” he adds. “I think it might be different for women, though. My girlfriend said that she’s afraid of ‘coming out’ because she might be thought of as a slut.”

Living with two male partners

Tara, who doesn’t want to give her surname, is also a hinge in a V relationship, and lives with her two male partners.

“They both have separate rooms, and I spend two nights of the week with one and two nights with the other,” she explains. “There’s a lucky balance there. The two guys are very fond of each other; they’re like a cross between two very good flatmates and slightly competitive brothers. It’s pretty much the same as any other relationship: eat dinner, watch Game of Thrones, maybe play Scrabble, or dance around the kitchen when Shake it Off comes on the radio. It’s just that there are three people involved rather than two.”

Much like Sinnott, Tara’s relationships happened by accident. “I went on a date with this guy, and he was like, ‘I’ve something to tell you: I have a girlfriend, although she knows I’m out with you’. I was like, ‘I don’t know about this’. We started off open and casual, with no inclination of closing it off. After a while I went out on a date with another guy, and he stuck. He was like, ‘Actually, this set-up really suits me’.”

Is it different for women?

Do female polyamorists encounter a different reaction from others? “Anyone I know who is polyamorous is wildly sex-positive and wouldn’t have any squeamishness about being seen as sluts,” says Tara. “Frankly, you don’t get into this kind of relationships if you care what people think.

“I always say to people, ‘Do you love both your parents? Well, you don’t pick one of them to love’,” she adds. “In a way I imagine it is what it would have been like growing up gay. You never see any relationships depicted in popular culture that match your own.”

Confusion evidently still reigns when it comes to our impression of polyamory, but the public might be edging towards a place of understanding. On RTÉ2’s hit reality show Connected, Elayne Harrington, aka Temper-Mental MissElanyneous, spoke openly about her relationships with her boyfriend and girlfriend. “Even as a child as young as seven, I found myself challenging social conventions,” she says. “For example, I turned vegetarian. This gives an idea of my mindset, even then, in terms of morality and making decisions based on opinions I had independently formed.”

Harrington makes a distinction between polyamory and open relationships: “Open relationship suggests there is little or no agreements on conduct, responsibility or consideration,” she says. “A polyamorous relationship is one with a different type of openness: open-mindedness, and an open heart. Love is a unique, personal, emotional experience. I felt all the traits of falling in love, none of which were Disney-inspired.”

Harrington’s appearance on Connected has prised open a dialogue for an audience previously unfamiliar with polyamory. “The feedback I’ve received has indicated that the viewers have appreciated that [frankness and openness], whether they agree with my lifestyle choices or not. No one has felt the need to impose their beliefs on to me, as I have not on to them.”

Irish traditional society has long been a powerful moderating force when it comes to matters of the heart, and monogamy seems unlikely to die out as the dominant model. Still, for anyone who feels left out of that one-size-fits-all model, the option to try another route to emotional happiness is here for the taking.

Polyamory Ireland’s closed Facebook group is facebook.com/groups/polyamoryireland