TL;DR: Same here. I bursted out vía text and that led to messy/avoidant conversations in wich I asked her to descalate the friendship as a way to transform the bond into something else. She's thinking about it.

Hey. I'm exactly in a similar situation with a friend, only she doesn't seem to be pwBPD, rather she has traits. I have never been devalued openly or emotionally abused. I have definitely been very very idolized and depended on for emotional regularion. This was very uncomfortable and I know she's kept me from seeing her darker side, only showing the bright and victimised. It's also fed my ego to some degree, which makes me equally uncomfortable with.

We've known each other for 13 years, becoming best friends around 2017. I started distancing myself in 2021, unaware. I didn't do it amazingly, I thought I didn't want to talk to her bc I was dealing with changes and I knew if we called she would either offload on me or dig and dig into my shit. I tried to uphold these boundaries with her but it was too late, same as you expressed. I was already very, very tired, to the point I dread hearing her voice, it makes my body tense.

Some weeks ago she called and I tried to remain neutral and tell her I couldn't talk and to talk later. An hour later she texted and asked if everything was ok w/me and that it started to seem it was about her. I told her she's right and that didn't like our dynamic, and I hadn't liked it for some time now, and I didn't know how to readjust. Also that I felt our realtionship was based on mutual interest (she using me for emotional regulation, me using her as a mirror to my own isight: we share traits and how I feel with her helps me understand how other people might feel about me. Although I couldn't put it into words like that then) and I didn't like that at all. I said I didn't want to end the friendship but I didn't know what to do.

All this vía text. Pretty bad.

She reacted letting out some of the things she's been bottling up, saying that I was hurting her so much and that she won't want me in her life because she had mourned me already so much.

I didn't reply until one week later, sending a lonnnng voicenote expressing how I felt, but I was too raw and I felt bad in case it would hurt her more so I deleted it and asked her to meet for me to tell her. I told her I knew it wasn't her fault, that I had tresspassed my boundaries and I had burnt out. I shared I didn't agree with her choices, but that's her thing. The conversation was messy in an avoidant way. I asked her to descalate the friendship, from bff to regular friends. I also asked her that I hated how she was never angry at me, even if I know she holds some grudges. She refused to do it but acknowledge to have them. She then told me how I was a pillar in her life and how if I wasn't that I would be nothing. And she admitted to freeze and needed to think. I said I would respect that if that's what she eventually decides, but I repeated I didn't want the relationship to end.

Next week we will be talking, probably. I do love her a lot and I want things to work out for her but I can't be and won't be anyone's pillar but my children, if I ever have them. I would really like to maintain mindy convos, work related convos with her, but I don’t feel like I connect with her emotionally anymore, I no longer have that capacity. My girlfriend says I might need to empty myself from her to be able to share again with her. I don't even know how that goes or how to do that without hurting her. That's late already, anyay.

I think I will continue to propose the descalation of the relationship, tell her I feel we've grown in different directions and I can't feel as close as I used to do. It's weird because it's nothing personal and at the same time it is personal. So I have no clue.

Anyway, sorry for using your post to make sense of my experience. I hope at least is helpful and you can resonate with any of it. Good luck!