sometimes my fiance (living together for 3 years now) will ask if she can eat a certain food in the fridge or pantry that might be kind of designated for me but it's only out of courtesy
she doesn't actually need my permission cause if i told her no she'd probably laugh, say "too bad", and eat it anyways. our relationship isn't on edge like that though...we share everything
but this is a whole other topic of discussion... and if you aren't married or don't live with a significant other there's no way you can say either way cause all those preconceived notions of what you think is yours and hers goes out the window