In Canada, even before I was married, I referred to Mike as my partner. In my experience it's not uncommon to do that in Canada. My mom always called Mike my partner and I had heard it repeatedly before that. I liked the neutrality of the word. I hated the word boyfriend, which always felt inadequate after so many years together. Plus we were partners - common law, in every sense, according to Canadian provincial law. I liked the seriousness, the legality-sounding of the word. I liked that it connoted equality and accurately described our relationship.
I would have probably referred to Mike as my partner forever, but then we moved to Malta.
When we first moved to Malta I would sometimes get strange looks when I referred to 'my partner' or people wouldn't understand (or would pretend not to understand) what I was talking about. I switched to 'boyfriend' and later, 'fiancé'. It was just easier.
Now I call him my husband because I think it's a pretty word and because it's always understood. But sometimes I still throw in the word partner, too, because I think its important that people get used to hearing it so we can all (regardless of our sexuality) have a vocabulary for love that is normal and useful and doesn't raise any eyebrows.
When I talked to some American friends about this they thought it was strange that I had ever used the word partner, and I thought it was strange they never had! So what do you call your significant other and in what situations (and languages)? I'm genuinely curious.