(Image: STEVE WELSH)
Hospital wards, mortgage lenders and divorce courts would all have to make room for polyamorous relationships under policy up for debate at the Scottish Greens conference.
A motion from the party's Greens of Colour group says people in multi-person relationships are being failed by the law.
It says: "Poly relationships are growing in number across Scotland but remain without recognition in any part of our lives.
"This poses difficulties for those in these relationships by leaving space for misunderstandings and ignorance when interacting with others, including public services, and legal barriers where recognised relationship dynamics otherwise have support.
"This can prevent members of poly relationships from visiting their partners in cases of serious illness or being recognised as their partners in official documentation. It can lead to additional and unnecessary complexity when it comes to financial affairs, leaving many unprotected where traditional relationships would not be."
The policy, if enacted, would see sweeping changes to legislation.
On housing, it says: "For housing all appropriate regulations and mortgage agreements should take into account the potential for cohabiting relationships to consist of more than two people."
It would rewrite how divorce works, by ruling that consensual non-monogamy cannot count as adultery as grounds for ending a marriage. It would also make benefits, universal basic income and pensions, healthcare access, inheritance, and immigration and asylum rules take account of more than one partner.
The motion also calls for a "commitment to counter discrimination" through equality legislation covering employment, property, healthcare and harassment.
Schools would be affected too. The motion says: "Sex and relationships education should reflect key principles of consent and mutual respect and support in relationships without prescribing specific relationship structures as superior or inherently more desirable."
The party would also swap the word "couples" for "partners" in its existing policy on LGBTI+ equality and housing duties.
The idea has been around the party before. A version was referred back in 2023 after discussion before conference, and it was brought again in 2025 but was not heard. This year it has the formal backing of the Greens of Colour committee.
Rachael Hamilton, the Scottish Conservative deputy leader, said: "The Greens are completely detached from reality and have their priorities utterly wrong. While Scots are being hammered by soaring bills, crumbling public services and an NHS in crisis, the Scottish Greens are obsessing over giving polyamorous relationships a legal makeover."
She added: "This is the sort of bizarre political navel-gazing that makes people despair of Holyrood. Ordinary Scots want politicians to fix the problems blighting their lives, not indulge every niche ideological obsession."
Max Bannerman, a Reform UK MSP, said: "This motion is the latest desperate attempt by the left to outdo itself in the race to be simultaneously the most extreme and the most detached party in politics."
Ross Greer, the co-leader of the Scottish Greens, told the Scotsman the party is a "democracy" and members can bring forward motions to debate.
Nowhere in the world offers marriage on this basis. The nearest equivalents are Massachusetts city ordinances allowing partnerships of more than two adults, Canadian court rulings recognising three legal parents, and notary-registered unions in Brazil that regulators later barred.