The Warlock's Hairy Heart in Tales of Beedle the Bard by J. K. Rowling

The main character is a handsome, skilled and rich young warlock who sees emotions as a weakness, and decides to prevent himself from ever falling in love by using the Dark Arts. The Warlock is deluded and he believes himself to be envied for his splendid and perfect Solitude. This makes him all the more upset when he overhears two Servants talking about him. One Servant is taking pity on him, and the other Servant is making fun of him for never having a wife. The Warlock decides to find a beautiful, talented and wealthy woman, so that he is envied by all.

The Warlock meets this woman the very next day. The women is fascinated as well as repelled by the Warlock, but agrees to attend a feast at his castle. The Warlock attempts to flatter the young woman, but she confronts him saying that she would only believe these lovely words if she thought he had a heart. So the Warlock takes her down to the dungeon of the castle and shows her a magic crystal casket, within which lies his own beating heart.

Due to the fact that the heart has been parted from its owners body for so long, it has become shriveled and hairy. The women ask him to put the heart back inside his chest and so he does. The women is so pleased that she runs forwards and embraces him. The heart however has become horrible in the long time that it has been separated from the body, and the smell of her hair as well as the beauty of her skin pierced it.

Other guests who had been attending the feast, were beginning to wonder where their host was. So they searched the Castle and eventually found him in the dungeon. The Warlock was sitting crouched over the woman, caressing and licking her heart, while she lay dead with her chest cut open. He was trying to swap her heart with his, however his heart was strong and would not allow it. The Warlock did not want to be controlled by his heart so he cut open his chest and ripped it out.

For a brief moment the Warlock was victorious as he held a heart in each hand, before he fell over the woman and died.

I am the warlock who's decided to lock his heart away.