He doesn't reply to your texts nor answers your calls yet he doesn't want you to leave him. You will have to let him know the facts. He has cut communication. Without communication, a relay can't survive or be strong. It isn't healthy. While you understand the relationship might have some effect on the relationship, cutting the communication isn't the solution. He has to know he is hurting you. His action is rude and it displays an attitude of 'I'm-not-into-this-relationship-anymore.'
You have to arrange when to meet to discuss. If he doesn't reply or answers your call, send him a text. Explain to him how you feel and why you his attitude is indicating he's no longer interested in the relationship. He has to make a stand whether he is in it or not. You are a human with feelings, dreams and goals to fulfill and things to do. If there is no constant commy however infrequent it is, you won't continue in the relationship.
You have to find a way to solve this issue. If he doesn't want to communicate through these channels, you will have to end the relationship.