I need a word, or words, to describe a very common social phenomenon that has no name of its own. Can you help?

The local political leader is re-starting the social discussion about the 'registration' of same sex couples for the purposes of allowing the legal system to recognise rights and such things as the transfer of property.

What is trying to be avoided is calling the recognition "marriage" which, it is felt, has a very particular meaning as being between a couple which is composed of different sexes. Equally, there is a very functional word -- partnership -- for a couple composed of different sexes who are not married but who choose to be 'partners'.

I went back to the Latin roots for words, and found "adiungo".

adiungo -iungere -iunxi -iunctum [to join to , connect]; 'adiunctus fundus', [neighboring]; of immaterial things, [to associate, impart]; of persons, [to attach], esp. as partner, friend, etc. Hence partic. adiunctus -a -um, [bound to, belonging to]; n. pl. as subst. [collateral circumstances].

The formal process or legal binding can be an "adiunctum". The person who performs this would be an "adiunctor".

I figure that the words in English closest to these are "adjunct", meaning (as I think of it) something closely bound to the other thing.

It even leads to a very Australian contraction, "ady" / "adie", as in "Meet my adie..."

I will not claim to be a Latin scholar. Have I got these correct?

Now, have I got anyone thinking? Will it catch on?

References:
* Latin Dictionary and Grammar Aid - University of Notre Dame, USA
particularly
* adiung
* adiunct

_____
Peter

PS
I also played around with another Latin word, that is very 'suggestive' in English and certainly intimate sexual conversation.

cum (1) prep. with abl. , [with, together with; at the same time as]; 'cum eo quod','ut', or 'ne', [on condition that].