Have Hope, not sure if this will help, but going back and forth on ending a relationship is common. In Codependent No More, the author says that codependents will generally take the alcoholic back something like seven times. The same holds true for relationships with other dysfunctions. She says that's part of the process and nothing to be ashamed of. It's not only normal, it's sometimes necessary (her words).

You didn't let him come back because of a fault in you. If anything, it was the more giving aspects of your personality that gave him a foothold. That whole process has brought you to where you are now. It sounds like now you have come to a place where you are no longer second guessing yourself. That has to be worth something.