Talking endlessly about highly personal stuff that a normal person would only disclose to someone he/she knows well or to a therapist like being sexually abused, like on a first date, is not appropriate.
This is a bid for connection. Remember that people with BPD do what we do, but on overdrive.
Here's a pop psychology article totally unrelated to BPD:
16 psychological tricks to make people like you (with notes by me from the pwBPD's perspective)
1. Copy the person you're with (as in, be what they like)
2. Spend more time around the people you're hoping to befriend (as in, constant contact, get mad you're not spending time with me)
3. Compliment other people ("the connection" people often point back to)
4. Try to display positive emotions (idealization does this on autopilot)
5. Be warm and competent (this is a maybe, but they can be)
6. Reveal your flaws from time to time (except all of them, at the same time, as soon as possible)
7. Emphasize shared values (or steal them from them, no inner sense of self right?)
8. Casually touch them (sex, great sex, sex immediately)
9. Smile (you're in love now, easy)
10. See the other person how they want to be seen (Idealization again but with extra mirroring)
11. Tell them a secret (or your whole traumatic youth, whatever is convenient)
12. Show that you can keep their secrets, too (this one I'm not sure, but its often about shared childhood traumas)
13. Display a sense of humor (this is common human behavior, your BPD's mileage may vary)
14. Let them talk about themselves (and their traumatic/codependent upbringing, easy)
15. Be a little vulnerable (be ALL of the vulnerable)
16. Act like you like them (well, you do like them, they fill their needs now, easy)
I think most of us in this group want to trust again and have healthy relationships with friends and romantic partners, yet we don't always trust our internal radar which does show us that something is not quite right, by the behaviors of the person who turns out to have BPD and how we respond.
Because we are also "desperately" seeking that connection.
Many members are codependent, saviors, fixers, empaths, people pleasers. we want to believe because it makes (made) us feel good about ourselves. We don't "trust" our intuition not because its wrong, but because we want to ignore them red flags for the sake of connection.
And what an intense connection it is.
I fell in love with my exgf because she allowed me to be romantic with her, I loved that she loved what I told her, I loved to get a reaction out of her, and I loved that she told me that she'd never felt like that before.
I don't know if it was true of she was just talking to get me, that's my own insecurity right there, but I loved every minute of that, and I do recognize now it had more to do with me and how I felt than with making her feel loved even if that was my "conscious goal".
It was over the top, she would play along, lead me to it, playing the damsel in distress, made me feel like a man, important and powerful, she would say "I love you have things figured out", but also made me feel caring, a protector, telling me about her terrible past and her troubled relationships, I thought "for sure I'd be the one to make it right".
And as perfect as she was then, she went straight to what she thought was my core: I'm not man enough, I'm worthless, I just needed attention and you sucker fell for it.
She missed by a mile with those, that's not were my self esteem was, I was (probably still am) insecure about her being truthful about her desire for me. I questioned her often on it, demanding "proof", "giving her a choice" (to leave basically), ended up pushing her away.
I know why I fell for her, and I don't regret it. I never got the worse of BPD (or maybe I minimized what I did get), worse she did was have sex with other men but even then we weren't exclusive, just felt hurtful that she would do it since she knew I hated cheating. We weren't exclusive, but we were seeing each other regularly.
Anyway, that's my experience. too much disclosure already? that's how I fell for my BPD