Eat your heart out
The ancients believed that sorrow or envy were bad for the heart, and would eat away at it, each sigh draining blood from the organ. This idea made its way to England and became well established - Shakespeare often refers to it, as in, 'Might liquid tears, of heart-offending groans, / Or blood-consuming sighs recall his life, / I would be blind with weeping, sick with groans, / Look pale as primrose with blood-drinking sighs' (Henry VI, part 2, III.ii). We still describe someone as broken-hearted by grief. By the beginning of the 20th century, to eat your heart out was well-established as a term for pining; but more recently, it has also been used as a cry of triumph when someone else has cause to envy the speaker
Found in a phrase dctionary online...