Well, it depends on how you two keep your money. Do you combine your paychecks and spend that for everyone? Or do you two have separate paychecks? One person pays rent, another affords food, one buys clothes, the other affords trips.
If you follow the first, yes, it is wrong and completely upsetting. I would take the stuff he bought and bring it back or at least have a long talk with him about money spending and sign us both up for a Dave Ramsey course (I've already taken two of them but I can do it again).
If the second and you have separate paychecks, no. I wouldn't be bothered in the least. I know that when he needs money or runs out from his own stupidity with money, he will be running back to me for his lunch money. Just like he always does. Then I'll be taking us on vacations and being the one in charge of bringing joy to both of us. :) Just the way I like it. I love when he depends on me for something. Makes me feel valuable and making someone happy.
However, I would be more upset by him hidding something from me than him spending money, this goes for both situations. We would be having another long talk about that as well.