Hi Me-Time-
Have you been begged back? How have you dealt with it?
A borderline feeling abandoned will go into pull mode, to try and pull you back to soothe those feelings, react to the emotion of the moment. You likely know that.
You can deal with it by defining the goal, and deciding what to focus on, which you already have:
I keep reminding myself of all that I've been through and how it always starts up again (focus shift)
I can never take her back. I can't save her. (Definitive statements)
But it's hard because she takes ownership of her problem and she makes me feel like I'm turning my back on a wounded child. She tells me she is a frightened child and that's why she lashes out.
People don't really have the power to make us feel anything, we choose to feel an emotion based on what we make things mean yes? And she may consider herself a frightened child, while also realizing that presenting as a frightened child to you will evoke your rescuing tendencies, so that's a handy way to attach to you emotionally, and sounds like it worked. Just a possibility, apply as applicable.
But how do you deal with this emotionally?
By emotionally detaching, which is a process with stages (check them out over there ---------->, and includes grieving the loss of the relationship and processing all of the emotions that come up. Some people can and do detach while still communicating with their ex on some level, some need to stop communicating entirely to give themselves emotional distance, neither one's right, the one that works to achieve the goal is the right one for you. And the only way out is through, significant emotional involvement usually includes significant emotions on the way out too, but it's also an opportunity for profound growth, and opportunity to learn and grow, on the way to your bright future. Take care of you!