There are several synonyms for the idiom "eats one's heart out." Some similar phrases include "pines away," "grieves deeply," "laments," and "suffers in despair." These expressions all convey a sense of sadness and longing for something or someone that is out of reach. "Eats one's heart out" specifically implies a feeling of consuming emotion, as if the heart is being devoured by one's own sorrow. Other related idioms include "brokenhearted," "soulful," and "heartfelt." No matter which phrase you choose, they all capture the deep emotions and hurt that can come from unrequited love, loss, or unfulfilled desires.
