i would not cast a spell over another. morally i feel it's wrong. try talking with him. if you feel you need a magical way out, look into a love spell that doesn't cast over someone, but just asks for a new love to enter your life. a honey jar spell would work to bring a new love into your life. i'd have to poke around for a spell to help someone get over another. try and be friends and let things run their course, if it's meant to be, it's meant to be, if not, it wasn't.
sorry i'm not of much help, just try and heal, maybe the two of you will come together in the future, or you could find someone better.