We've been together a while and, in 99% of situations, I still say "boyfriend". If I say "partner" it still sounds weird every time it comes out of my mouth. And I've always been somewhat of an entrepreneur, so people have gotten confused at times, thinking that I'm referring to one of my "business partners".
But once in a while I'll purposely say "partner" - for example, I was speaking to my financial advisor last week and used "partner" multiple times, mainly to give the impression that this is a serious, long-term thing and not just some guy I met at The Cock last Saturday night.
Of course, now that there is marriage in NY state, things get interesting. I've had people ask "is he your partner or your husband?". And then the inevitable, "so when will you be getting *officially* married?". Thankfully, although we spend most of our lives in Manhattan, we are, technically, residents of New Jersey, so it will be a while until I have to address that one