Metanoia (Change of heart)

This story is about a teenage man named Gray. He has a girlfriend whom he loves so much that he could sacrifice his life for her. Nonetheless, the girl seemed choked by Gray's too much affection, the reason why she broke up with him and love another man. With immense pain felt by Gray, he has this troth not to love a woman anymore but instead a man. Would his love be effective with a man? Would a man reciprocate his feelings back?
BEWARE: yaoi