He needed time and space to heal.
This you must give him by leaving him alone. If you read these threads, you will find most people can only heal by not being in contact with the ex, and this is highly recommended for healing ones self, so please respect his wishes.
I am only trying to be friends. Is he still hurting and punishing me?
He is not ready for what you want, and its not about you, its about him coping, and adjusting, so don't take it personal, but do respect his need for space at this time. You don't push friendship, as it should be mutual, and equal, and for now, its not.