I know a few people who put a huge stash into crypto because they don’t want their spouses to know about their money when they get married.
That doesn't make sense. Rationally, hiding that money in secret is a reason that the marriage won't work out. Hide that money, tell lies, be a scheming and awful person, and there will be a self-fulfilling prophesy of that marriage not working out.
Open source (this time in the form of full disclosure and a prenup agreement) is the way to go.