Brynn and Doll had been together romantically for nearly three years when they sought out a new partner through an online dating website for threesomes. That's how they met Kitten. They all hit it off, which eventually led to a commitment ceremony this past August 2013. Since then, Kitten became impregnated with sperm from an unknown donor.
This throuple claims to be the first of its kind -- but I know at least one four-person plural marriage that got together locally under circumstances back in the 90s. They also had a kid together. Within a year of that, the relationship fell apart. But the concept is the same.
This throuple is not legally married, through they had a lawyer draw up paperwork to equally merge all of their assets.