My suggestion for a clear diffinition between the two different forms of union with a totally different use of words is also something that would REALLY help the averagfe person get a heads-up before going to a social event.....(ie a marriage or a Civial union)

In the real world it would break down to being like this:

You open your mail one day and find an invitation to a co-worker's child's "marriage"

From the use of the term "marriage" you know a head of time what to know this will be an event where a man and a women are going to be united in legal union.

However lets say you open the same invitation and see you are asked to attend the union of Cris and Pat in "Domestic Partnership"

Now you know a head of time to expect that this is a union between two people of the same sex.

Everyone walks in the door of the church that day knowing what to expect, and no one gets grossed out, pukes, or points fingers. Everyone there "understands"...

Everyone there knew going in what to expect to see going on...