When Brittany Loignon began exploring polyamory after her marriage ended, she quickly discovered her relationship choices could be used against her.
During a heated custody discussion, her ex raised her polyamorous history as a way to question her fitness as a parent.
“It was just thrown at me as a threatening piece,” she said. “It set off an alarm — like, can I actually lose custody of my children because of this?”
Loignon, a Toronto-based therapist, says some of her clients have reported similar concerns.
She has seen long-term partners be unable to advocate for an ill partner in hospital settings. She has seen a partner who helped raise a child have no legal recourse to remain in touch with the child after a split.
“Even if [the third person] is deeply integrated into family life, helping to raise the children, contributing financially, doing things with the household, there’s still this underlying fear that if something happened, they could lose everything overnight,” she said.
Data suggest a sizeable number of Canadians are in polyamorous relationships. Yet polyamorous families are not generally recognized in Canadian law — leaving them to rely on informal agreements or private contracts to define their rights and responsibilities.
“I think this must have been what it was like for same‑sex couples 40 years ago, going to lawyers trying to get their … rights and responsibilities of their relationship defined,” said Hilary Angrove, a family lawyer in Toronto.
“The lawyers couldn’t help them because that was against the law.”
Multiple romantic partners
Consensual non-monogamy describes relationships in which people have more than one sexual and/or romantic partner with the knowledge and consent of everyone involved.
Polyamory is a form of consensual non-monogamy that includes emotional attachment and romantic love.
While data is limited, a 2019 survey in the Journal of Sex Research indicated about two to four per cent of Canadians were in open relationships. The survey further suggested about 20 per cent had engaged in non-monogamy, and 12 per cent identified it as their ideal relationship type.
Canadian law does not recognize such relationships as legitimate.
All of the provinces define spousal relationships as being between two adults. Ontario’s Family Law Act, for example, defines a spouse as “either of two persons” in a marriage-like relationship.
Federally, criminal law prohibits “any form of polygamy or any kind of conjugal union with more than one person at the same time.” It also prohibits people from celebrating, assisting in, or being party to ceremonies or agreements to recognize such relationships.
Angrove says this law is “like a blunt instrument trying to strike a specific harm.”
The law, which dates back to the late 19th century, aimed to prohibit polygyny, a form of polygamy where one man has multiple wives. Historically, these unions most often occurred in Mormon communities, says Victoria Clowater, a PhD student at McMaster University who studies polyamory and the state.
A landmark 2011 court case considered the constitutionality of this criminal law. The case centred on a fundamentalist Mormon community in Bountiful, B.C. Evidence presented in court showed polygyny was linked to gender inequality, younger marriage ages, and worse outcomes for some women and children.
The court upheld the law. “[But] the judge decided that [the criminal law] did not apply to polyamorous relationships,” said Michaël Lessard, a family law professor at Université de Sherbrooke.
The court took the view that polyamory was different from polygyny in that it was egalitarian, transparent and relatively informal, says Lessard.
But many polyamorous relationships today are long-term, economically interdependent family structures that can involve shared parenting and cohabitation, Lessard notes.
Angrove increasingly sees this in her own family law practice. She sees two to three polyamorous groups a year who are seeking legal advice about their relationships.
Most of these clients, she says, are “responsible, intentional adults” who discover the law does not recognize their relationships.
“If you all live together and you have a house together, when you split up, it’s the [original couple] that have rights,” said Angrove. “If you’re the third to be added, you do not have rights.”
When relationships break down, that can leave the third partner with no claim to property or support, even after years of contributing to the household’s finances or caregiving.
Angrove often relies on co-ownership agreements that treat partners as real-estate co-owners rather than family members. She has also used shareholder agreements that structure relationships like business partnerships.
“You can do whatever you want between shareholders,” she said.
But those workarounds do not enable the third partner in the relationship to access protections afforded under family law.
A third partner still cannot access spousal support, for example. And while some courts recognize more than two guardians for a child, there is no consistent framework extending full rights to all caregivers.
‘Improves societal life’
While some sources said they would like Canadian law to recognize multi-partner family structures, others say monogamy is a socially beneficial legal norm.
Peter Jon Mitchell, a researcher at the Christian-informed think tank Cardus, says monogamous marriage produces measurable social benefits that justify its special status in the law.
“Societies adopt monogamy as a norm because it improves societal life together,” he told Canadian Affairs in an email.
“Does polyamory produce the same level of family stability? Does it produce the same outcomes?” he said. “I’m not sure we can say that it does.”
Mitchell cited 2012 research linking monogamy to more “peaceful and prosperous societies.” He also pointed to a 2016 study showing a “marriage advantage” in health, income and child stability.
However, both studies compared marriage and non-marriage households, rather than monogamous and polyamorous households.
This gap points to a challenge: Canada does not collect data on polyamorous households.
Statistics Canada says its census design does not capture multi-partner family structures. As a result, “it does not always reflect the full complexity of families,” the agency told Canadian Affairs.
Zoe Duff, a polyamorous mother of six with two male partners, says that invisibility persists today.
“The 2026 Census is still exclusionary of polyamorous households as it clearly defines common-law relationships as restricted to two persons,” Duff told Canadian Affairs in an email.
“I look forward to a time when polyamorous households are counted.”
Fifteen years ago, Duff was involved in the Bountiful case on the constitutionality of Canada’s polygamy prohibition. At the time, Duff and her two male partners lived as a single family unit but lacked legal recognition and felt unable to formally celebrate their relationship.
“We are unable to entertain any thoughts of ceremonially recognizing our relationship,” Duff was quoted saying in 2011 court filings.
For Clowater, what matters most is that individuals in polyamorous relationships be able to access the same “systems of care” as spouses or common-law couples.
She pointed to spousal health benefits as an example: currently, individuals in a three-partner household would only be able to designate one partner as a covered spouse.
Lessard, of Sherbrooke University, says family law should recognize not only romantic relationships, but also other forms of emotional and economic interdependence, including long-term cohabiting friends or relatives.
“If we look at emotional and economic interdependency, we see a bunch of other relations … brothers and sisters, or friends who live together for a very long time,” he said.
Loignon, the Toronto therapist, says institutions are lagging behind social reality.
“Love doesn’t always exist within one simple container,” she said.
“A stigma still exists culturally, but people are evolving faster than institutions … which largely operate from a more archaic relationship framework.”
