BPDFamily.com

My ex and I broke up at the end of March after a 5 year relationship. I initiated the breakup, it wasn't because I didn’t love her or didn't want a future, but because I couldn’t keep surviving the constant threats and ultimatums around marriage and children. I wanted those things too, just not under coercion.

Within two weeks of the breakup, she was already sleeping with someone new. Within a week after that, he was staying over for full weeks, basically living there half the time. I know this is probably part of regulating herself, but part of me wonders if this was at least in part to punish me, otherwise why let me find out?
I've since learned this is common with BPD, but that doesn't make it hurt less, it completely shattered me.

She still reaches out in some form every week or 2. I’ve mostly stopped responding, and that only seems to increase her messages/calls. It’s clear she genuinely misses me, but she's at least now choosing the new relationship. And I still miss her deeply too, but I'm not telling her that.

The paradox is this: she would be nearly my dream partner if not for the other side. She’s one of the most thoughtful, loving, generous, kind people I’ve known. But when she feels threatened, especially around abandonment or not see future commitment from me, she turns to emotional blackmail: guilt-tripping, threats of breakups or donor babies, triangulating others, and at times, suicide threats or minor self-harm (which I believe were coping mechanisms, not manipulation, but still had a coercive impact).

It’s incredibly hard to reconcile these two parts of her. The loving and the terrifying. And what makes it worse is her complete inability to acknowledge the impact. When shame comes in, it’s all DARVO, I become the problem, and she deflects responsibility. And yet, she’s so smart, successful, capable in so many other areas, in her career, socially, general life. It’s baffling.

I know my role too. I fawned, appeased, backed out of promises I wasn’t ready to make. I avoided hard truths. I lost myself in trying to keep the peace. But I’ve been doing the work. If we both took responsibility, I genuinely believe something beautiful could grow from it. Our day-to-day compatibility was strong, when things were good, they were really good.

But my heart and head are torn.
My heart still wants her.
My head says walk away.

So my question is:
I know plenty of people would have come back from this. But has anyone actually come back from this and rebuilt something healthy, mutual, and secure?
After there were already problems in the relationship
After the BPD partner entered a new relationship immediately
After the break was messy
After deep hurt and betrayal

I'm having so much trouble letting go of the good side of her, which is the one there most of the time.

Those are all tough questions, and the answers are even tougher.  There are success stories to be found here from those in your situation, but it requires a lot of growth from both sides of the relationship.  For example, could you forgive her and actually let it go?  Can you understand BPD enough to realize why she jumped into another relationship so quickly?