I think people are far to critical of Carnival. I have been on them 27 times and never had a problem. They have a 98% repeat factor. They are the only cruise line that has a Vacation Guarantee. I have also been on HAL, CEL, PCL, and as mentioned above Windstar. I think you would enjoy any of them for just yourself and wife. All the cruise lines offer the art auction, wine tasting, are up to date on the internet cafes, and have the intimate fine dining restaurants. They all have been hiring celebrity chef's to redesign their menus. But each cruise line has their own specialty that makes them a little different. I particularly like CEL's thalassotherapy pool. Very relaxing. CEL also has a new acupucture program, they have computer and camera classes, martini bar, and the Bar at the Edge of the Earth. HAL has their "Signature of Excellence" where they have updated cabins with fine high thread count Greek linens, special massage shower heads, deluxe waffle and terry robes, fresh fruit baskets in every room. Suite categories have premium plush Euro mattresses, luxurious duvets and pillows. They have a new culinary arts program. PCL was the first to come out with the outdoor theatres by the pool. Now Disney and Carnival are both getting them.
Since you have gone several times on RCL I think CEL and HAL would both be a good choice for a cruise without the boys.
PS: Did I read in another thread you are prior Air Force? I'm retired Air Force 20 Years. Lajes Field, Azores; Langley AFB, VA; Wallace AS Philippines; 339Recruiting Squadron Michigan