I think you are trying to find something within you to blame for the way things unfolded. I guess it’s easier to rationalize things this way and to absorb some of the blame in order to avoid the real truth. The real truth being that this wasn’t a healthy relationship. The reality is that you were a willing participant in a vicious cycle of highs and lows. If you truly had genuine moments with her, I don’t believe you’d end up where you are today. Genuine people don’t act this way.
Please learn to alter your mindset from the current one which is that you feel your self involvement may have been the cause of all this. The truth is, you must learn to focus on you, your needs, and why you’re drawn to certain people. Stop being preoccupied with “could haves”, “would haves” and “should haves”. You’re in the way of your own progress.