If you aren't telling your spouse ...
then you have some secrets. simple as that. could be big secrets could be small ones.

not everyone is an "open book" there are different personality types.
And yeah, how do file your taxes without your spouse knowing?
maybe this?
Married filing separately is a tax status used by married couples who choose to record their incomes, exemptions, and deductions on separate tax returns
i guess it's theoretically possible for a man and wife to not know much about the other's finances. at least here in the usa.
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 here you are on the world's most popular cryptocurrency forum.

i suppose, like satoshi, you have taken care of that though.
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 were incapacitated; why wouldn't I trust her to know we own bitcoin?
i don't think it's about that. it's more about someone's personality type. do they like to gossip with their friends and can't keep a secret? if so then someone like that might say something you didn't want them to. some people have big mouths and you just can't trust them to keep their mouth shut about something you'd rather other people didn't know. truth.