I've suggested a Bitcoin wallet as a wedding present, held as a multisig with a notary they both trust, with the prenup describing when and how much will be added on certain occasions (upon engagement, after the honeymoon/consummation, on birth of child, on anniversaries, etc.) You could do something similar with a gold vault or ETFs. Or some combination of those.

Arrange payment in advance of divorce or death, and arrange it in a form that is highly portable and liquid, and that doesn't require his assistance.

(Disclaimer: not financial advice, just how I think I'd do it.)