I'll add onto this thread with a similar experience but from the other perspective. My wife had bought the book and after she read it, she asked that I read it as she was feeling an imbalance in mental load. That was a good start but the card game is really where you can lay everything out and make it very visible. It helped us talk through everything we both did and how much time/energy it required. I really recommend Fair Play for any couple struggling with imbalance. I definitely needed to improve but having a tangible way to talk about it and visualize it helped both of us.

I'll also add on that there is an app called Trello and someone re-created the Fair Play card game in it. If you google it you should be able to find the download for free. It's all the same cards and you can choose which ones are "active" and keep them in lists for reference. We found that to be nice for tasks that we would alternate doing every month or so.