Food waste

Hi beautiful coaches,
Please excuse the utter ridiculousness of this scenario, but I’m sure it’s the door to something else so please bear with me!!
My partner has recently moved in with me and his attitude towards using up leftover food is very different from mine and I’m trying to figure out where to go with it. Please help!

C: He threw a once-squeezed lemon in the bin
T: That’s so wasteful
F: Irritated
A: Think of how I would have been more efficient with the lemon and how he is wasteful in other ways. Think about the money/time etc I spent on getting the lemon for its one squeeze!!
R: I waste my energy

I don’t want to be OK with food waste and I enjoy being efficient with leftovers.

Where is the middle ground in this? I have done a thought download and discovered that I hold a belief that efficiency and non-wastefulness is a good thing. I don’t want to change this belief but I also don’t want to be irritated over such a trivial thing.