I’ve been concerned about her reason not to do it actually. It was why it didn’t work.
You definitely know her more than i do, but has she ever told you that she suffers from depression? Anxiety or any other mental obstacle?

She probably needed your help to make her first step, and progress with the relation.
As long as she seeked no other partner, then it’s safe to say that it was not you who was the problem.
I’m not saying this to make you feel culpable, but have you tried to speak to her? Have you pointed out your concerns and thought of guiding her rather than resolving your personal issues over helping her too?

It could be late to approach her with anything for the present time, but that does not prevent you from getting a profound understanding on her and the relation. She was your ex, and she still matters, no matter what you do.