I broke this guys heart... I feel horrible, what should I do?

It's a long story and all, but I guess it all started when I told this guy I wasn't happy with our relationship. We had been going on and off for months now, fighting a lot and then making up some now and then. When we first went out we were happy and in love, but the years have gone by and I feel totally different. He's hurt me and it's scarred me. He went out with someone else and so did I. We both seemed so unhappy around each other (note that he is a very sensitive person). I told him I loved him and he didn't believe me. He said from everything we've been through, you're going to have to prove that to me. I thought to myself, isnt he supose to accept what I did? I realized he didn't really love me. The next day I told him about this and he got really pissed off. He said I shouldn't ever deny his love. I told him that I don't think we loved each other and that we should accept it and move on. He told me he accepts that I don't love him but he'll never stop loving me. I don't understand how he could do that. I told him I was going and he said so that's it then? just forget all about me. I told him I'd never forget him and left. So my question is, what should I do? How can he still love me like that after everything? I feel horrible about breaking his heart again. I'm totally lost and I need some advice. Also note that he is stubborn and won't reply to my texts after this scene.