Frank - You weren't able to deal with things. SHE'S not able to deal with things. She's no more or less screwed up than you were/are.
Forgiveness is a gift you give yourself. Let go of this resentment, let go of HER,and just start paddling for yourself, okay, hon?
Perseverating on how she let you down is NOT helping you. Focusing on what she is or isn't doing is not helping you. You can't change the past, but you CAN create a better future for yourself.