Relationship with an ex. Definite problems. Advice?

Okay, so I started sort of (as in unofficially) seeing my ex again. This is about the 5th time. No joke. Every time before, he's either lied to me, cheated me, played me, or our general relationship just got screwed up. So last time, he had left me for a friend of mine, and they dated for about two months or so. They broke up, so now he likes me again? I know him pretty well by now, and I can tell that his last relationship changed him. And, things are different now because we've built a better friendship and trust each other more. So, he keeps changing his mind about this, going back and forth saying that he wants to be together, then that he doesnt. He says he was really just hurt last time. Is all of this worth it? Or am I just being a trusting dumbass again? How can I make this work...because it's extremely important to me, and something I really want.Relationship with an ex. Definite problems. Advice?
You say you can tell this last relationship CHANGED him yet in the next senstence HE still cannot make up his mind. Sweetheart- this is not going to be exactly what you want to hear. Give him the end of your boot once and for all! You have given this man MORE than his fair chance of chances and he has BLOWN it each and everytime! You deserve alot better than a man who is going to lie, and cheat on you. DUMP him now and move on with your life. There r alot of men out there who are loyal and good to women! Good luck to u