Am I being daft?

So I drove my husbands car today and I found a screwed up label which was off some flowers. It said ‘scented rose’. I just asked him when he got in what it was for because I happened to open it thinking it was one of my receipts. He has said it was a plant pot and he took the label off, didn’t tell me who for. He said I shouldn’t be asking him as it shows mistrust. Now he is angry with me.

We have been a bit rocky recently and I’m now all upset because I feel bad for asking but at the same time why is it so wrong to ask?