I mean, if they have any doubt it begs the question why they got married in the first place; since they're signing a document which basically means they're entitled to half of everything.
If you aren't telling your spouse you are involved in bitcoin at all, then you are hiding all your exchange accounts and forum accounts from them too? Do they not question why you have bank transfers to and from centralized exchanges or random individuals if you trade peer to peer? Or do you have a separate hidden fiat bank account that you use only for bitcoin? And yeah, how do file your taxes without your spouse knowing?
Instead, protect against not revealing you have Bitcoin to the public, and only to those that need to know.
Absolutely this. I preach complete privacy when it comes to the wider public and corporations. There is no need for Facebook or Google to know that I own bitcoin, and there is also no need for Facebook or Google to know what my hobbies are or where I like to shop. But when it comes to your close family members, then it is a different story. I trust my wife to make life or death decisions about me if I was incapacitated; why wouldn't I trust her to know we own bitcoin?