Should I Move On?

A guy and i have been on & off for 3 years, we would go a while without talking but when its all said & done, we would still have feelings for each other.

This last time was the first time i really gave him a chance. He messed up (found a picture of him kissing someone).

I know that more than likely he isn't worth my time. He just doesn't get "it", has a lot
of maturing to do.

I do believe that he messes with other girls, i know he does, his own friends have told me so.

He's a liar. But even knowing all of this, i still sort of want to be with him. I don't know when or if he'll ever realize he has a good thing.

I'm not even sure if its me wanting to be with him, my not wanting anyone else to have him or me not knowing when i'll meet someone that i find attractive and is mature enough that keeps me around.

What should i do?