But that doesn't mean each person needs to have both of their names on each bank account (that could be worked out with a will, death certificate, etc), or the private key(s) to bitcoin addresses. The important part, as the OP is asking about, is how to make sure the spouse can access those accounts in case something happens but without incurring too much risk to the paper wallet. Those are all good suggestions with multi-sig identifiers. One solution is multiple encrypted copies of paper wallets spread among family and close friends, with only the spouse knowing the password. That would decrease the risk of accidentally opening up a paper wallet.
The next question is what to do when there are kids involved, and you want to make sure they can access the funds in case both parents die in a car/plane/speedboat/space shuttle accident. I think it's a little bit too risky, but Hal Finney choose to put his keys in a safe deposit box for his kids: https://bitcointalksearch.org/topic/bitcoin-and-me-hal-finney-155054
+1 This.
Firstly, congratulations to you! I am also engaged and my fiance is actively involved in learning about and watching the Bitcoin ecosphere. When we marry next year, the money will be combined, simple enough.
If you aren't going 'prenup', then likely it's shared property. Hopefully, you'll want that, anyway, and won't be 'sneaky' about your assets, which doesn't help you do anything but increase your ability for deceit. But, nothing wrong with wanting to consider holding those assets back; it'd be better to be honest about your concerns now, than to just lie to her, or keep it secret, IMO.
Thanks for the interesting conversation. You crazy rabbit.