dh and i have been there hundreds of times, and NEVER with a child! there are so many great restaurants to eat at, nice spas, and beautiful resorts all on disney property. if you go in october (maybe for your anniversary?) you can hit the food & wine festival, which is amazing. i like a lot of
@HouCuseChickie's recommendations...
-stay at a deluxe resort - or DVC. saratoga springs and old key west are beautifully themed, but are not mickey-heavy.
-plan out restaurants! maybe choose one character meal just to show her the magic - book later times to try and avoid more of the rambunctious kids. 1900 park faire was one of our favorites and is a very pretty restaurant... and it gives you the opportunity to see the grand floridian. california grill is a great romantic option. we're doing chefs de france for the first time on our next trip in october. we also love the atmosphere at beirgarten. and saana at animal kingdom lodge villas is great - beautiful views and a very nice menu.
-check out the fireworks packages. they have cruises which are not cheap but might be really nice. or plan out your own thing - find someplace neat on property you can view. like from the contemporary - get some drinks first, then go watch the fireworks before going back to the hotel. ditto at the poly, watch from the beach.
-there is other stuff off property. orlando outlets aren't too far (not great, not horrible). beaches aren't too far either; maybe you could do 3 or 4 days at disney, 3 or 4 days at a beach in daytona or cocoa beach. there are casinos within a couple of hours drive.
-or consider a disney cruise! there aren't any rides, but she could get a taste of disney magic. they have excellent food, some child-free restaurants, and so many child activities you don't really see kids all over the place. plus the ship will dock at some really beautiful, relaxing beaches.