Even Shares?

Its funny the way things occur to me.

I was shopping at the local Tesco, having been sent by Wifey with a list of things 'we need'. I dutifully went and filled the trolley with said items while she went back to bed.
As I was waiting for the scanning to commence, items laid out on the belt, I observed what I was about to pay for.
Meat, veg, fruit, cake, bread, juice... The usuals.

Then I weighed up the ratios. Our meat, her wine, our veg, her juice, our bread, her cake, our, her, our, her... Hmmm.
There wasn't anything that was exclusively mine, or for Number 1 Son, but there was stuff that was exclusively for Wifey. Quite a lot of stuff, actually. In fact it came to 25% of the bill.
OK - that doesn't seem too bad, after all, there are 3 of us, and 1/4 of the bill for one person? Ah, but the other stuff isn't mine or Number 1's exclusively.
We don't eat stuff that she doesn't like. Fair enough. But I only have a very small list of things I don't like. And she still buys them for herself.

So... is it me? Is this the way everyone is? Or am I just being taken for a ride?