Not permanent? Her or the boat??
Ohhhh,.. I get it! She's a keeper, but you want to still have your "alone time" on the boat.
In that case, you want option "A".
Stuff some noodles and PFDs in the stern and throw her back there with the cooler. Tell her to hang on tight. If she does not complain about the hard, wet ride or facing backwards, you will need to up your game. Pass her to handpump when the hull starts filling with water and be sure to make a crack about her weight. (You'll only need to do this once, BTW).
Or if she's fearless and athletic, there's always option "B"
[youtube]http://www.youtube.com/watch?v=FTJPq4DGhJQ[/youtube]
This might keep her interested for awhile.
But if you want her to savor sailing as much as you do and are willing to let her drive - get the tramps. (Option "C"). It will make her day. I'm sure she's beautiful as well, and would make a stunning hood ornament out there. (As a plus, the boat will sail better too).
Fast forward one year; if all goes well, (on the water and at home) then a TI would make a great anniversary present (ask Mitch and Cindy). Hobie will have their kinks worked out by then too.
Please note: this is "marital" advice I'm giving now, not "maritime" advice, which I have far less of!

Best wishes to you both.