Ok - I don't know what planet you guys are living on....hiding your wallet from someone who you're supposed to be able to "trust," hiding credit cards....switching out real jewelry for costume....tucking MORE money into his wallet so he doesn't feel embarrassed (or whatever your reasons are)....WHAT the WHAT?!?!?!?
The old folk taught me a lesson early on: "Romance...without finance...is a bad chance!" MARRIAGE with financial SECRETS has an even WORSE chance of survival! Money secrets in a business, family, friendship or marriage is comparable to knowingly building a house on a cracked foundation. At some point the house begins to lean, shift and finally, can no longer pass inspection because the foundation is no longer in the place where it was intended! Once the foundation of a house(marriage) shifts (dependability, trust, thinking of what will best benefit both parties and not just one's self, working together toward a common goal rather than living together, but maintaining separate lives) instability has an open invitation into the house(relationship). (It is just so ironic that we share our most intimate selves and moments with our spouses, but fear to discuss money....it's absurd)!!! The Bible says that "money is a shelter." In another verse it says: "money answers all things." Married persons with messed up money issues that they refuse to confront, will either live the rest of their lives with a tremendous amount of angst and anxiety, or, end up paying even MORE money to the divorce attorney!
Money is a foundational building block that many times has the potential to destroy a relationship quicker and more permanently than an indiscretion. This man is either ignorant (no disrespect intended...we are each products of our environment). Many people who were never taught while growing up to handle money, become adults skillful at hiding their fiscal ignorance, unless or until they're confronted.
This man is either: squirreling away money for reasons that he doesn't want to share with you (not good..,if he wants to have money of his own so he doesn't feel like he needs your "permission" every time he wants to buy a candy bar, the adult thing to do is to just say so), gambling, doing drugs or, seeing another woman. Painful considerations all, but very realistic possibilities.
By joining in on his deception thru hiding your knowledge of the truth, you become complicit AND duplicit. Do not enable his behavior. Let him know that you want to talk about it, lay all of the cards out on the table so no one is left in the dark concerning the other parties actions or intent....and work on building up the trust level from there.
There is an excellent game called "The Un-Game" that you might want to play with just him, as a way to get the conversation started. Steel your nerves, don't back off, be the big person in this for the sake of the marriage, and who knows....you two might create a rage among other married couples who are going thru the same thing.
Find a way to deal with this and converse with (not confront) him, but by all means don't put this off any longer.