Your heart was directed towards a person. The king of curses. Sukuna was aware of your feelings towards him and had fun playing with them. You weren't in a relationship but he kissed you anyway, just to hurt you better when he went to see another woman.

He wraps his arms around your waist, pressing his chest against your back and nuzzling his head into your neck before whispering. “How are you, my favorite woman?” he had just said that to another woman on the phone, and he knew you knew.