This is a contingency plan that might be very necessary...if your spouse doesn't know about your assets then it just shows that there's no trust...you are not just telling people close to you just to let them know that you have Bitcoin saved up somewhere but it might come in handy..There are people that have died without telling anyone about their assets or seed phrase and in the end all the investments becomes a waste
If there is no trust in the marriage, why get married in the first place? Although there are times when you have some kind of experience in marriage where your spouse will display some kind of behaviour that will quickly make you start to be suspicious of him or her when it comes to your finances, in such a case you can only give them a hint about holding but won't give the person full access over the holding until times of emergency.