I think now is the time to try to reflect on what it is that you want to do. You have your ex, who I am sure that you care about, and he more than likely cares about you. However, he is telling you that he does not want a relationship with you right now and wants his space. I think that it is accurate that he only wants you around on his terms.
I also know that if he is telling you that he does not want a relationship right now, then no amount of talking or waiting is going to make him change his mind. He is going to have to come to that conclusion on his own. I think the best option for you is to be his friend, but to also begin to date other people. It is not fair to you, to wait around for someone who does not know if they want a relationship nor can they tell you when they will be able to be in a relationship with you. I know that it hurts and I know that it is painful. But the pain will continue if you stay in this tug of war with him.
So begin to date and get out more and start to do things that make you happy. If he really loves you, then when he is ready he will come back and he will be ready to talk to you about moving forward. What he is going through, may be something that he needs to deal with all on his own and may have nothing to do with you. This could be why it is hard to get back where you were, because he may have unresolved issues that he needs to deal with before getting back into a relationship with you.