If one of you is a cat, and the other of you is a person, there are certain rules.
One of these rules is, no matter how much you wish it to be otherwise, the one of you who is a person must, before retiring to another room for even just a moment, place some sort of protective covering over the bacon bits on the sideboard next to the spinach salad. Because if you do not do this, the one of you who is a cat will shortly be discovered (by someone else, in this case) with his entire head brazenly in the salad bowl. You must either learn to "cover up, buttercup," or learn to go without bacon bits in your spinach salad.
This is just the way it is. No amount of yelling, scolding, training, or flat-out cussing is ever going to make it any different.