RSVP Envelope

I would put you and your fiancé. Even though technically he doesn't live there, it's still your wedding. Most people don't pay attention to the address on the RSVP envelope.

I put just our first names.

I have my RSVP as my parents house even thought neither of us live there (we're moving soon and don't know what our new address will be in time). Our return address looks like this:

Nicole & Matthew

street address

city, state, zip

Put both names. We did just our first names and I think it looked great!

Put both your names

As PP said, just you and FH names should work well.

Perfect! Thanks everyone! I'm going to just put our first names on the envelope.

We put both first names and my address (he hadn't changed his address yet).

Who is paying for the wedding? Traditionally-whoever is HOSTING the wedding is put on the RSVP and invites return address. For me, even though my parents hosted/paid for the wedding, I put my and DH's home address on the RSVP address and my parents on the outer envelope return address simply because I knew my mom would not be able to keep track of RSVP's the way I wanted.

Ours say "The Future Mr. and Mrs. Last Name".