So the vows I said when we were in California were "Do you Glitter take Partner to be your life partner?" and I said "I do" and then they said "Do you Partner take Glitter to be your life partner?" and she said "I do" and then we kissed. Four sentences.
What we're each writing for wedding. Now that's the serious stuff. That's the can't-eat, can't-sleep, reach-for-the-stars, over- the-fence, World Series feeling kind of stuff we'll be saying. The stuff that means something. Four sentences we already said? That's what we had to say to get legalized in another state because our state won't allow it. Because we are modern Americans who are told they aren't allowed to get married in their state because other people get upset when two chicks wanna get hitched.
I've never wanted a commitment ceremony. And I don't like that no matter what, that's apparently all I can have. Because other people think I'm less then. Because our relationship isn't as good as a heterosexual relationship. Because we aren't allowed to get married in the state we call home. Because until last year, even the federal government said we weren't worthy enough of those rights. We weren't good enough.
So, even before we over-turned DOMA, even before we overturned prop 8, I said wedding. I wanted a wedding. I'm having a wedding. I'm going to stand up in a pretty dress in front of my friends and my family in the state I call home and make loving vows to the woman that I love. And I'm not calling it something else because I'm different. Because I'm not. Because our relationship is not.
Our legality isn't a secret. We're both terrible at secrets anyways. But it's not announced. We see it as a step. For us to make this commitment we have to take certain steps. Our steps have to be separate. Even though we live in the good ol' US of A, we have to have separate ceremonies or have a destination wedding. Those are our choices. So we've taken one of our steps. I still call Partner my partner. After our wedding, she'll be my wife.
Now I know, the OP is talking about a straight couple. But given what I get to go through, I can't fault a straight couple for still wanting their wedding to be their wedding, even though circumstances don't always allow for the legal part and the celebration part to be at the same time.
Though I think we're saying "Wedding Celebration" on the invites. Partner saw it somewhere and thought it was cool and sounded like a fun thing to go to. But as far as we're concered, it's our wedding. It's when we become wife and wife. And had we gotten the legal bit done after the ceramony (because again, we can't do it in our state), it'd still be when we became wife and wife.