It all depends on the partners' preferences. In my case, I am very much open when it comes to my social media accounts, my husband knows my password. We have the same password in Almost every acounts that we have including phone passkey. It alk goes down to how much you trust your partner.
In my opinion, why would you want privacy over social media or anything if you are not hiding anything, i guess, if one can tolerate this, sooner or later it can be an avenue for cheating. Just my two cents.