I am on a cash basis only. I have a card for emergencies. We also have an agreement that any purchase over $20 should be ok'ed by the other.
I do not have a debit card either. There was only one time that I actually scared myself the urge was so strong I gave him my bonds and my card.
I like the idea of a safe deposit box...it does buy time.
If you think you could do it, maybe getting rid of the cards would help. Cutting them up or even microwaving them works pretty well.