Thanks for your post. It was really interesting to read and think about all of this with you.
It's interesting, last year as I was searching through and trying to figure this out I ran across a description online about BPD. I was going back and forth over whether he was bipolar or BPD, and now I wonder if possibly both, but... .He had already acknowledged he was "unstable" and he noticed his motions were erratic, so I just sent him an online quiz about it and he later read a description and he said "oh, that's me!" It was good for me to hear he agreed with what he read, frankly I was less sure, but he saw it at that moment. But that was us!
So, while it's a good idea not to tell her you KNOW what she has, you could suggest perhaps, I think, that she look at a description and see if it makes sense to her, ya know? But that is just my opinion. I would back off if she was super negative, but in my case, it gave him some sense of relief and he immediately wanted a "cure". I had to break it to him that it didn't quite work that way.
Perhaps you just leaving all these books around could be a big hint that you are thinking about this stuff and might make her curious. But also, remember, that even with a diagnosis... .Well, what you really are wanting, I'm hearing, is an acknowledgement that there is a problem and you probably want her to commit to do something about it? But can you also be okay if that does not happen? After all you do know what it is most likely and the only part you can really control is your response to it. You can't change her, but you can encourage her to work on things together at her pace.
You could also just say you are gaining a lot of insights from your own readings and you are learning how to be a better partner to her. That might get her interested and asking you for more information. Or not.
Diagnosis or not perhaps you could just focus in on the verbal abuse and take her a bit off the defensive by saying you want to learn about communication together so you can improve things together. It might help her understand how and why you are setting limits. I think the more we can get away from a "they are bad" "we are okay" stance, the more chance we have to help their defenses come down. But I know, easier said than done.
But I notice lately that when I can hold myself when he starts attacking and validate his feelings, listen past his attacks, and listen for the feelings and respond to the hurt I am hearing then I have a chance to see a faster resolution. It is not easy. He constantly interrupts and throws verbal bricks at me. I am taking a hail of fire and I don't always feel well... .do I block the bricks or stand there defenseless and let them hit me? But instead of that I guess I mentally melt the words/bricks. It's a lot of explosions and drama, but when I can see past all that to the basic feeling and needs being expressed and rise to the occasion of that the battles are cut off a bit.
I wish you well!