The Scottish Greens are pushing for legal recognition for Polyamory.
The traditional 2 person relationship has legal protections, which aren’t accommodated in a multi party relationship. But I can’t see marriage rights ever extending beyond 2 people.
The absolutely crazy party of the motion is this bit.
“Where immigration rules or laws of asylum involve existing relationships with those already resident or citizens in Scotland those rules should take into account relationships that may involve multiple partners.”