This falls into the category of don't rock the boat! I think it is not a good time to delve into this.
My situation is the same with my husband. He works, but can't pay bills on time and avoids doing the taxes. This has led to trouble, and to stay out of trouble, I have taken it over. I would not be happy to have him suddenly start tearing apart the check statement. I try hard to make things work out but there are always unforeseen costs- the wedding present for a friend, the new tires for the car, the traffic tickets, the roof repair, etc. Having someone stand over me and insist that I "stick to a budget" when emergencies come up and can't be avoided, makes me angry. I have been married for 30 years and the only reason we are still married is that we no longer discuss this. My husband has made it clear to me that he is "very concerned about the finances", and I do my best to keep costs down. But I don't duck bills, and if it means a transfer of a bill to a credit card to get it paid, then I do it. And if he stuck his nose in and started asking questions, we would be off the races on arguments.
Maybe your situation is better than mine and there is enough money to go around. But if you are not already arguing about money, then don't start now! I guarantee you this will start the mother of arguments!
My father always said there were only two things married people fight about: money and sex. If you are already arguing about one, don't start in on the other.