With my wife not wanting to hear of any word about "what if...", it's even harder to find a way to do this.
You are lucky, you have somebody in the family that understands crypto. I don't have this luck.
Bitcoin is not even my biggest concern (I'm not rich yet). It's the altcoins, of which some may have a future.
And with so many types of wallets laying around, making a list of coins, files, websites, passwords, would be too big and highly unsafe.
I would be happy to find a very good solution. For now the only one I have in mind is a text file with all the details I can gather, password protect that file and keep it somewhere at hand (USB stick?).
Of course it'll make sense only when she'll accept to talk on the "what if" subject, so I can tell her about the file and password. And actually get to make it.