I caught my wife via chat logs, she was having an emotional, if not physical (that I could never prove and just looked past) affair. He actually told her that she should go back to me. This was near the end of our 2nd year of marriage, we have been married for 14.
Honestly, since that time, I don't know if she had cheated on me up until she abandoned me and our 3 children almost 6 months ago. Now I am pretty sure that she has. Have multiple social media post showing that she was involved with someone as soon as she left.
I am aware of her BPD, because of my therapist, through doing some joint sessions with her and her therapist. I am not in your situation as my goal was not to perpetuate the cycle of abandonment for my wife, and I intended to stay no matter what transpired. This I did knowing the work it would take. I would need to make myself a better person, and not wait for her. She was/is in denial of her BPD. She would have lucid moments where she would recognize the issues, but then she would "go into hiding" and blame me for all of our issues all over again.
6 months ago she split me black and made a very sudden decision to abandon me AND out 3 children 11, 10, and 3 years old. She left the state and moved 1300+ miles away and was living with another guy. I believe that this relationship has since expired.
I have accepted that she has an issue which I cannot help with other than being supportive and she no longer wants my support (I enabled her too much anyways).
The question for you is what you can take? The kids make it difficult as I can almost guarantee that it will be drawn out and probably will get ugly. If you are focused on yourself (I am saying that if you are focused on making yourself a better person, not indicating selfishness or anything like that), and you are making progress there, that is all you can do. That is the decision you have to make.
YOU CAN NOT CHANGE HER... .she would have to want that for herself. If there is already a lot of resentment towards her as it sounds like, then that is something that you need to resolve for yourself first.
One saying that I use is: Resentment is like taking poison and waiting for the other person to die.
Essentially, you have to forgive FOR yourself. Sorry for my ramblings, but this article is saying most of what I am trying to say.
https://foreverymom.com/mom-gold/how-to-forgive-someone-even-when-you-know-theyll-never-apologize/