I think, that if you are serious about healing/working on yourself...you learn from those kind of mistakes.
Do something against your moral code? Then figure out the whys and learn from it. Don't repeat the same mistakes.
If someone is only giving you pieces of themselves, and not all of themselves, it will never work out into a healthy relationship. It is hard to see it when you are IN the relationship, you just know something is off.
If she wants to be with you, she will make it happen without excuses. If she doesn't, either the relationship isn't right, or she has some issues she needs to work through.
Bottom line, I know...for ME...I don't ever want to be someone's "savior" in a relationship again. Supportive, yes, sharing...yes...but "saving"? No. I would want to see that she is actively working on herself, you should see the changes, before giving her another opportunity. I do think people heal and change, I know I certainly have. In the beginning, I wasn't nearly as pulled together as I am now and accepted too much crap. I gave out some crap too, and he called me on it.
So, count it as a learning experience and go look for what you really want and deserve from a relationship. You don't have to close the door to her, you can leave it open a little while she works on herself.
Taking a chance is never a bad thing.