Ensureing credibility

Spouse A has a account in madien name
Spouse B registers online for account access to Spouse A account
Spouse B Has access to view account and copy account data is this legal yes or no ?
Spouse A has given Spouse B - credit card, debit card, and or cell phone to use in any way sees fit would online access be a part of the service with implied consent to registor online with such item?