I don't understand how some women can not have a clue as to how much she and her husband are worth financially.

I still have not made up my mind on pre-nups.
When one spouse is very wealthy and remarries for, say, the third time (think Donald Trump) after paying millions in previous divorce settlements, then he/she may want to protect themselves from gold diggers but for a first marriage that's hard to justify.

One guy who should have had a pre-nup for his second marriage but went against the advice of his financial advisors and is now being taken to the cleaners in his divorce is Paul McCartney.

In California in a divorce everything earned after the date of marriage is considered community property and is split evenly. If you brought money into the marriage that belonged to one spouse only (say, money received by that spouse from an inheritance that took place prior to the marriage) then that belongs to that spouse alone even after marriage.

I don't know but I am guessing that no matter what checking accounts, savings accounts, IRA's, etc. you keep in your name alone it won't make any difference if you live in a community property state. I think state law regarding assets in a divorce (or ownership of assets brought into a new marriage) all depend on the laws of the particular state where the marriage took place. A lawyer would have to answer that one.