I do believe your feelings are very deep and sincere for this woman. However, this woman has a problem with low self-esteem. If she doesn't love herself, then it's impossible for her to love anyone else. Usually, women with low self-esteem seek out those who treat them badly (consciously or subconsciously) and are actually put off by those who treat them with much respect. Women with low self-esteem feel that men who treat them with respect are somehow weird themselves because how could a man possibly love a woman who is "defective."
My advice would be to keep in contact with her, but don't be the one always initiating contact. Let her make the effort to talk to you or spend time with you. Trust me, she will appreciate and respect you more. That is, if she does reach out to you. If you are always at her beck and call, she will take you for granted.
Women with low self-esteem lead somewhat self-destructive lives and can destroy your emotional health and your life literally in the process. Every relationship she has had has failed miserably, so it becomes a self-fulfilling prophecy. She is her own worst enemy.
If you want to wait, then do what feels right for you. But, do take a good hard look around. Don't feel guilty for finding someone else who is interesting to you. She obviously didn't put much thought or give much consideration as to how you felt or your feelings regarding her trip to see her ex.
Sometimes, women like that can change and sometimes they don't because they don't recognize they even have a problem. What you can control is your actions and reactions towards her. Put yourself first always.
I've dated many women with low self-esteem unknowingly and am still single. Reach your own conclusions... For whatever reason, I attract them in droves. Some of them were some very lovely women and I had some great times, but they couldn't or wouldn't deal with the major issues in their lives. I would have gladly supported some of them through any difficulties.
I'll never think badly of those women, but they obviously weren't the "one" for me. It took a little time to find that out though. Well, excuse the long-windedness and hope this helps. Good luck!