Cutting One's Heart as a Guide

He once knelt in the snow for three days and three nights, begging me to cure a woman for him. I cut open my heart to make medicine, but he turned around and married her as his concubine. Later, I became the enemy's military doctor. In front of the two armies, he asked me frantically: "Where is your heart?" I smiled and pointed to the woman behind him: "It's over there, Your Majesty."