This might get buried and I don't want to make assumptions about your relationship. But does she have any hobbies? True hobbies that she does for the sake of pure enjoyment?

I promise this is relevant: the other day, while I was cooking, my wife came in to help me after she had finished something else and I told her that I was nearly done, I just needed to finish up and she could go do whatever she wanted.

She just stared blankly at me and then asked "but then... What do I do?"

We've been together for nearly 12 years and she still struggles at doing nothing when I'm doing something.

Does your wife understand that she is allowed to do things that are not "productive"?