Hi Shelly!
I think the most romantic resort is the Polynesian, followed by the Wilderness Lodge, and then the Grand Floridian.
With no children, I would personally spend a lot of time in Epcot, especially World Showcase. I think walking around the Pavilions at night is romantic, especially if you linger a little bit after the park is officially closed and take your time exiting. While there, consider dining in Bistro de Paris or Les Chef de France in the France Pavilion. Bistro de Paris is much more formal and, in my opinion, more romantic of the two restaurants.
I also suggest dining outside of the theme parks as I think it can be a little more romantic. I recommend Victoria and Albert's in the Grand Floridian, California Grill in the Contemporary, Jiko in the Animal Kingdom Lodge, and Artist Point in the Wilderness Lodge. If your budget allows, the
Chef's Table at Victoria & Albert's is an incredible experience.
Before my wife and I had children, we enjoyed dining in Cinderella's Royal Table. However, I think it can be a hit or miss depending on how you and your husband enjoy the characters; if you do go, I recommend requesting a table near a window with a reservation that allows you to be there during the Wishes fireworks spectacular.
Speaking of fireworks, you might also consider a Magic Kingdom Wishes Cruise or an Illuminations Cruise. A "Breathless 2" cruise can be very romantic, especially during Illuminations. If budget is not an issue, the
Grand 1 would be spectacular.
Hopefully these ideas will get you started. Have a magical vacation!