It depends on the situation or personalities.
What if both of them are knowledgeable in crypto but have a different opinion on alt coins, or what if they are in a verge of breaking up?
It is good to have a partner with a similar mindset or have the same interest as you, you could both have your own investment or portfolio or just combine your investment to make it grow.
I agree with this. Sharing a Bitcoin account involves trust and knowledge of good custody practices. The couple might not be ready or in the same mindset about it.
Trust can also be challenging if one partner is not responsible with finances and frequently makes poor spending choices. What if your husband's financial habits put your family into thousands of dollars in debt, and you've paid down the debt on your own multiple times? Or, maybe your partner is responsible with finances, but has no interest in learning about Bitcoin. If they have no interest and are unwilling to learn about safe custody and how not to get scammed, I don't think it's good to share a self-custody wallet. Yet, I want my partner to inherit my bitcoin if something happens to me, and I still need to find a good way to do that.