>If I read your statement correctly, if my wife dies, her debts held under her name only are her debts, and even joint ownership property that would get tangled up in her estate aren't subject to settlement of her debts -- like they couldn't force me to refinance the house to take out equity to pay them off.
Wrong. A court may order a joint-owned asset to be sold to satisfy a singly-owned debt.
When you die, all your assets and debts are added up, both singly-owned and joint-owned. If you want to run up a debt before you die, you have to get all assets - including joint assets - out of your name, along with making sure the debts are not joint debts.
>he said that the inheritance remained somehow exclusive to her
Inheritances are a specific exception, and treated just like assets you owned before the marriage. What you do with the funds once married doesn't matter much - the source of the funds matter.
It's not really complex at all. My money is my money, your money is your money, and our money is our money. Anything earned during the course of the marriage (inheritances aren't "earned") is "our" money and normally split 50/50.