Eat one’s heart out

To grieve inconsolably or to be sorely vexed, eating one’s heart out is a very ancient concept that is found in Homer’s Odyssey (c.850 BC) and the works of Pythagoras some four hundred years later. Its first appearance in English dates from the late 1500s. These days the expression is more commonly used as a jocular boast to make someone envious as in eat your heart out.