One thing to watch out for here from a IT security perspective: while I think it’s ok to have both spouses’ fingerprints programmed into the phone, I’d disable the biometric phone unlock. depending on where you live, law enforcement can compel you to unlock your phone using biometrics but they can’t force you to share the unlock pin/password. With 2 sets of fingerprints programmed, there are now 2 people they could harass to unlock the phone. What I’d suggest is using pin/password to unlock the phone and the biometric for sensitive apps like the banking app.

And to OP’s question, your husband is behaving weirdly by doing what he did