I know some people object to the word "partner" for one's significant other because it makes it sound like you work together. Well, guess what? Rob and I do work together, like a well-oiled machine! (Well oiled.) We're managing a household, growing a family, and we're working at it every day. We are associates in life.
Unlike so many words connected to people and relationships, "partner" is gender-neutral. Mention to your invitees that partners are also welcome at the party and you've really included everyone: male, female, and other!
Some people argue that a husband is so much more meaningful than a "mere" partner. While I disagree with this on an etymological level (partner comes from "joint heir," while husband comes from "master of the house"; which of the two has more meaning is open to interpretation), it is certainly true under the law. We tend to reserve the words "husband" "wife" for legal marriages, and marriage is not equal right now. A "partner" is certainly less than to someone who cannot legally have a husband.
When I refer to "my partner" in a group of people who don't know me well, I could just as easily be talking about a woman. People look at me a little funny when I do it, which is part of the reason I continue to do it. It's a great way of challenging heterosexual privilege.
Even after six and a half years, though, I still find that "partner" doesn't roll trippingly off the tongue. It's a little clunky, as relationship words go, though I find it vastly preferable to "spouse." (Ick.) Also, as much as I like what "partner" suggests, "boyfriend" is way hotter. But I think if I suddenly started referring to "my boyfriend," my family would worry.