You may not be ready to read between the lines and look at the situation objectively just yet. If you're still at the 'mourning' stage for your failed relationship, you still need time to heal. If this is the case, wait until you're ready.

If you are at the stage where you want to understand what went wrong, you've already taken a big step on the road to recovery. The idea isn't to make yourself more miserable by going over the past: sometimes it's useful to go back and admit the part you played in what happened and the mistakes you made, if only so that you don't repeat them, you come out of this relationship with a better, more mature understanding of yourself...and you don't fall for any more love rats! 

Next: understanding why