Forgiveness covers over many a mistake.
To forgive her will start to remove the pain inside of you.
Forgiveness doesn't need mean full reconciliation back to what was.
To end things all she needs be told is the truth as you posted here...
You want to work things out by yourself as that will help you grow faster then relying on her for support
If she is like a family member of mine, she will move on when she feels she can't be of help. The family member of mine does that often. By befriending people and then looking for things she thinks she could help with is what gives her purpose. Not saying this person is like that but from what you posted, it sure looks like that same person in many ways. Intentions are good but may not be there if a time comes you really need the help.