Do I owe him an explanation?

tough situation, i know it must be hard for u, and would hurt. But i dont think u owe him an explanation that is up to u, i think u should talk to him though personally. tell him ur feelings an tell him u dont want it to be justs about . if hes a good guy he will understand and hopefuly make it right, if not hes not even worth it, hope it helps, and hope things work out for u :)