"Eats one's heart out" is a phrase that implies jealousy, longing, or regret about something that one does not have or cannot obtain. Antonyms for this phrase could be "content," "satisfied," or "happy with what one has." Instead of dwelling on what one lacks, these antonyms suggest being grateful and appreciating what one has in life. "Indifferent," "unconcerned," or "disinterested" could also be antonyms for "eats one's heart out," indicating a lack of interest or emotion towards something that others may desire. In summary, the antonyms for "eats one's heart out" promote positivity, gratitude, and nonchalance.