Notes defaults to the wrong icloud account.

I have more than one icloud account set up on my mac. My main account and my wife's. However, when I create a new note on my mac, it uses my wife's icloud account instead of my main icloud. This ***** because my iphone only syncs to my icloud. I tried looking for a way to change the default account, and I see a menu item for it, but it remains greyed out and unselectable no matter what account I have selected in Notes. How do I change the default account that notes are created in?

Andy