If you happen to be celebrating on a Wednesday, the Wine Tasting at 3pm at Jiko would be a wonderful way to start an evening. $25/person, and worth it. It takes about an hour.
I like the PP's suggestion of dinner at Jiko. I think that it is the most romantic restaurant on property (possible exception of Victoria & Albert's, but I have no firsthand knowledge of it... yet). Between the end of the wine tasting and a reasonable dinner time at Jiko, you may need to fill a good bit of time. You could schedule a massage at the AKL health club to fill some of the space there. They don't do a couples massage, but you can get simultaneous massages in different treatment rooms, if that's up your alley.
Then, drinks at the bar, and on to Jiko for dinner. After dinner, maybe head down to see the animals through night-vision goggles, if you want.
Wine tastings are only on Wednesday, and is a bit unique right now in terms of WDW experiences. The rest of it you can do any day, but might be better at GF with massages at the GF Spa and dinner at Citricos, or in the Boardwalk area with massages at the Mandara Spa in the Dolphin and dinner at Flying Fish (Chef's Table for a bonus!).