It will depend on the actions that you took in order to find your spouse’s documents. It is allowed to look at and make copies of account statements or other financial documents that you would be able to access in your normal day to day routine.
You can also make copies of account statements or other financial documents that you find lying around the house or in any other place you might normally go during your day. If you are required to take additional actions, such as opening up your spouse’s bag to find the documents in question then that does not qualify as a place you might normally be or go during the day and could make you liable for “intrusion upon seclusion.
