Chas, I think your wife's issue was that she was coming from a classical tradition, which is great, but I think it behooves us all sometime to put away the notation and try to feel it, play by ear, improvise...

Reading music is a very valuable skill, but for many it can become a crouch, and even a hindrance to music making.

My daughter is an outstanding violinist, currently in college majoring in violin performance, did not start note reading until she was playing for several years. This was by her instructors design and it paid off. We did a wedding gig together the other day, and she played 'Wave" and other standards, and she never opened the book. If she's heard the tune enough, she can play it.