I had a look for you. The people I know tend to use "partner" but that always sounds a bit businesslike.

Lots of the words in AWAD could find a new meaning and be used:

How about my Superfluous?
My Shangri-la
For the "Ladies" - My Panspermia
For the "Gentlemen" - My Bluestocking

I'm sure we can find some others if we look hard enough