Revisionist History in full swing.
These sort of things were nothing more than the Medieval equivalent of an S corporation. It had nothing to do with legalizing any sort of homosexual relationship.... which still would have put you frying at the stake before a Cannon Court. It was all about a legal contract governing property ownership.
Mostly this sort of thing would have been used by actual brothers or other individuals that had a blood relationship.
Medieval Europe faced serious problems with population growth and division of inheritance.... and developed various mechanisms to deal with it. Primogeniture was one of these... shared ownership like the contracts being discussed were another.
Essentialy, a plot of land that could easly support 1 man and his family in one generation..... couldn’t be subdivided indefinately among the heirs of succeding generations and still produce enough to support all those heirs and THEIR families. Figuring out methods to keep parcels of land intact through succeding generations was a huge deal for a relatively closed agrarian society like Europe. This was also one of the major primary drivers for exploration and colonization/conquest of lands outside of Europe.
Exactly!