Hey there,
Having been caught up many times in push-pull relationships where I felt so torn about staying or leaving, I really relate to your struggle here. What helped most for me was a lot of research into topics like codependence, Borderline Personality Disorder, love addiction and several fields that explain the deep reasons why we are attracted to particular people and what the very purpose of relationships are.
I just wrote a post that is detailed and covers most of what I know about these issues. It's called
Choosing Intimate Partners: To Repeat or Not to Repeat?. It might give you some more ideas about whether to stay or go (I've been dealing with the same question yet again lately).
Whether you do stay or go, now is a great time to gain insight about yourself and your relationship style that will help you for years to come. There are also a lot of resources available through that post that you might find useful. They are some of the most important things I've ever read.
Hope this helps my friend.