It seems like you know you will have to wait. He is a procrastinator and he told you he is not sure about committing (which means he does not want to commit at this time).
You have two choices.
1. You can wait and see - which means you may get married at some point or may break up at some point or may stay in a state of limbo.
2. You can leave and find someone who wants to get married.
Basically, you need to ask yourself which is more important to you. If you WANT to get married, then staying with a guy who doesn't want to marry you will probably be painful and breed unhappiness. But leaving is difficult too, I understand. You have to decide which you would rather give up: marriage or him. Good luck with your decision