I am one of those people that are somewhat lost when I am trying to figure out how to refer to people in same sex partnerships. Part of this is due to being in my early 30's and growing up in a relatively conservative pocket of the very liberal Pacific Northwest. I was out of highschool before any of my aquaintances came out, and out of highschool before one of my cousins came out. I attended a smaller quite liberal state school and had a couple of gay professors who were my first daily contact....and they both referred to their partners differently. Since then, I have tried to listen carefully to how people refer to their partners, gay or straight and address them in their preferred manner, but in can still be a linguistic minefield.
In any case, as long as they aren't being malicious or harrassing, I would just refer to your partner by her first name.
This is a good illustration of what I was trying to say. You seem to ascribe your own hesitation to the culture in which you grew up. But I think the more salient point is that the few same sex couples you do now know don't all use the same terminology. I bet if they all said the same thing, either "husband" or "spouse" or "partner" or whatever, even if it's just two or three couples, you'd naturally just go to that choice without feeling unsure.
Again, I'm not saying that people are wrong to want to use all different terms for themselves. But the inevitable result will be that people will be uncertain and forget or make mistakes. That's the whole pro and con of conventions and etiquette "rules": you give up particularity and personalization but gain clarity and shared understanding.
It happens in all kinds of areas, not just sensitive ones like this. Miss Manners warns against using overly "creative" wording on wedding invitations, for example, and I think she's right. If you request the honor of my presence at your marriage, I'll know to arrive ten minutes early. If you invite me to a celebration of your love, I might assume it is a reception of party with no ceremony, in which case I'll arrive ten minutes late.
"Wife" and "spouse" tell me you're married. "Girlfriend" tells me you're not married but are in an exclusive romantic relationship
. No, they aren't ideal terms, and they may not feel like they describe your personalities, ages, or opinions well, but they get the message of your status to me. "Partner" and "friend" don't tell me much.
And please don't use "lover" (red hot or otherwise). I suppose it is clear! But I would find it silly and probably obnoxious.