“If you try to sit on two chairs, you will fall between them. For life, you must choose one chair”.
The Russians say "you can't sit on two chairs with the same butt" .
The British say, "You can’t have your cake and eat it too”.
The Germans say, "You can't dance at two weddings at the same time".
But they all mean the same thing. They speak of making choices between two options that are mutually exclusive. That is, you cannot have it all. You have to choose one, which automatically sacrifices the other option.