Ever enjoyed fine music with your wife? If not maybe you should take her to a symphony, most larger cities have an orchestra. You may not have a symphony if you live in a rural area, but it is well worth the experience for most couples to try attending at least once. Granted depending on the music you and your wife like to listen too it might not be an experience enjoyed by all couples. If you enjoy fine culture and the romance of classical music, this could be a great date idea for you and your wife.
Be advised though that it is wise to dress for the occasion. A symphony is a good excuse for you and your wife to dress up and enjoy the elegance of the evening as you bask in the sound of violins, cellos, and timpani drums. This date may not be the cheapest date, but with some planning it is doable for most couples.
Afterwards, maybe dig a littler deeper what did the music make each of you think and feel? Did it inspire you or speak to your heart and soul?