You Can’t Have Your Cake and Eat It: Origin and Meaning

You cannot have two good but incompatible things at once

Once the cake is eaten, it is gone, so this idiom is used to show that someone cannot have two incompatible things. An early example of the idiom is found in a letter from 1538, which states ‘a man cannot have his cake and eat his cake.’

She works so hard to pay for that luxurious house but because she works so hard, she never has any time to stay at home and enjoy it. I guess you really can’t have your cake and eat it too.

Father to son: You’re living in my house rent-free. Most people your age aren’t living with their parents. If you want to keep living in this house you’re going to have to start paying rent. You can’t have your cake and eat it too.