Reddit reviews Psychopath Free (Expanded Edition): Recovering from Emotionally Abusive Relationships With Narcissists, Sociopaths, and Other Toxic People

Read this book
https://www.amazon.com/dp/B00SA4ZTWM/ref=dp-kindle-redirect?_encoding=UTF8&btkr=1

I was involved with one of these women and it took me 2 years to recover from the emotional abuse. And it is abuse. All the red flags we're there from the beginning, but somehow I allowed myself to get sucked in and even got engaged to her.
Now she's claiming we were never engaged or even in a relationship at all upon other lies so she can not return my ring to me, which is a family heirloom.

If she has narcissistic BPD, the TERF thing is probably more a product of that than anything.

That flip flop in attitude isn't really uncharacteristic of people with BPD: it's part of the 'splitting' aspect of things where there's no gray areas about stuff; love someone because they're perfect/hate them because they have no redeeming features or qualities. (Note that I don't mean this as an attack on people who have BPD, just observing that it's one of the flags of it.)

As far as that connection, the feeling like you can't let go, again, that's not super uncommon with people who've been used as a source for narcissistic supply. The reasons are complex, and may range from trauma bonding if there was abuse to a whole lot of other things. (I found this book helpful in understanding and sorting some of this out for my own self in my own situation: Psychopath Free)

For right now, it may be enough to understand that this is sort of what narcissists do - both creating a situation where you feel lost and awful and gutted by their rejections (so you have a hard time letting go, and keep coming back despite how they treat you - like in situations exactly like this), and the dropping people and cutting them out of their lives 'just like that' when they're done using someone (usually because they're not a good source of narcissistic supply anymore, or the narcissist has found a better supply elsewhere and it's not worth maintaining the old one.)

It sounds like it's time to go no contact, but getting free of things like this usually don't feel as liberating as people often think, at least to start with. Good luck.

>The rational male

That's quite a misogynistic book you recommended. I'd recommend Psychopath Free by Jackson MacKenzie, and googling the grey rock method (links included). The book you are suggesting is that all women have ulterior motives, and is based in how being emotionally manipulative towards women is the answer-it's rather short sighted and not based in psychological fact-only women bashing. I don't think that it's helpful to replace an abuse by becoming abusive. Rather, he needs to understand how to avoid these type of people by knowing how to identify them, avoiding them, and doing the self work to prevent it from happening again. Further, it will show him how to "grey rock" her so that he can protect himself while moving through the divorce process.