Some writing as I read

I’ve read that insurances are more inclined to pay for Bipolar treatment than for BPD, as BPD is considered incurable.
Yes, pw(people with)BPD often ‘stay connected’ with prior intimates, allowing them somewhere to flee…
I was ‘walked out on’ 6 times in 3 years, the 7th was me leaving.
You write well, very descriptive; you’ve the intelligence to see beyond this.
I can also relate to the trailing off of intimacy, too much emotional scar tissue. There are technical, or clinical terms for much of her behavior that I’ve forgotten, but they basically describe the behavior you are here, to me, classic BPD.
OK - it’s time to look out for you
! I’ve a good friend with Asperger's and have worked with Autistic students ... .and no longer need to imagine the effect someone with BPD could have on either… That was Hell, and it’s time to get out.
You did all you can for her, and obviously, there’s no limit to what she’s willing to do ‘to you.’ You’ve described a level of behavior that is unsustainable on her part. What seemed like the best of times were also a lie, not how you felt, but the fact they were unsustainable. So there is no reason for you to hang on. You gave her an opportunity to escape, there is nothing more you can do.
I suggest you find help for yourself … and interrupted my reading your piece to the end to tell you this. BPD is not her fault, but the behavior used to latch onto the unsuspecting can leave us devastated.
I know. What you’ve laid out here should explain to any health professional or counselor where to begin helping you. Use them - it’s your turn!
You’ve time to recover from this, and can. Do not focus on what you perceive to have lost - move ahead. And if moving ahead means retreating inside yourself in order to heal -- that’s still moving ahead. There are a ‘spectrum of women’ out there, with no doubt one who’ll be appreciative of your love. So get prepared. Counseling, meds till ya think it’s enough, focus on employment & career, reconnect with family, friends - with a focus on yourself.
Be aware, she will be back... .and will know how to get to you... So be prepared, which again, sounds like some serious counseling. No shame.
... .OK, finished your piece

I’m not an official greeter here, just someone who once felt as you do now, as I suspect we all have... . But you’re at the right place

Read, learn and share. And thank you, for being man enough to share your experience… Now make sure you’re around to advise others, when you're ready ~