As a man, married 31 years, I say it is joint money and you have a right to understand what any purchase over, say, $50 is for. You shouldn't have to walk on eggshells and he should not hide it. Just don't broach the subject in an accusing way. Be matter of fact.
I think it is good for couples to balance the checkbook together. We don't, because we have so many accounts, and she knows I budget out every penny. Neither of us has any vices.
