why not just both? usually married couples have shared money that they can use for the family and then they also have money of their own in which they can use to anything they want
i believe that that is the most ideal scenario here just because you are married does not mean you can't invest on your own as well we still need individuality and privacy even when married so if you could afford to do so then just have both the joint and separate portfolio but know that everything is for the better of the family
A joint bank account in Bitcoin wilouks he called a multisig wallet.
Just make two keys, give one to each spouse and set up a 2-of-2 configuration where both keys are required to sign off any transaction before it can be spent, and suddenly you don't have these problems anymore.