3 months isn't even that long of a time compared to 4 years of a relationship. You may want to talk things out, work things out, get some closure but he doesn't care too. He is still hurt, his feelings are still involved and nothing good is going to come of that. He is dealing with his hurt and problems like a child. If you keep pushing for it, he is just going to be defensive and pull away more.
Like dre said, now would be a good time to look at what was going on with your relationship and achieving an understanding of what and how things came to this will significantly help you out. You won't have all the answers because he will have most of them, and you tried but he isn't responding. You have to figure things best out on your own and soldier on through the hurt. He is the only person that can make you feel better but he doesn't want to.
I know your feelings are involved and emotions and it's tough to make sense of everything. If you talk about your relationship in full and honest detail to somebody that isn't biased (i.e. us) maybe we can provide some insight. We don't want you making the same mistakes again do we?
Waking up next to a beautiful girl,
Step outside and say hello to my beautiful world.