SIGNIFICANT OTHER,&c.

[sagehen]

I'm inclined to agree with Rick's & Larry's judgements on all the cited
terms, except that I rather like both SO and partner. "SO" because of its
vagueness has a sort of  levelling effect, as much as to say "these unions,
of whatever kind, are all equally important to the people to whom it
matters."  There is also a slightly pompous resonance there which
introduces a light-hearted, comic quality. "Partner" has the endearing
sense of equality and co-operativeness which recommends it. Though married
for 50 years, I have never much liked using the terms "husband" and "wife"
in reference to my own life, so I like these new developments in the
vernacular.
A. Murie