I think for me, the closest I have is the "friend break up" I had with my former friend D. We met at a local rock bar just after her birthday in 2011 and had a very intense connection, and over the next several months ended up roommates (I guess technically I was her tenant), then a few months after that she moved from the UK to NC to be with her LDR and husband (or at least, he was last time we were in contact). We then spent a solid chunk of most days messaging on and off, and I'd usually spend at least 1 night up until the early hours of the following day hanging out online with them, chatting nonsense and playing some games to spend time together. In 2018, she had some family visit and she started pulling back out of nowhere without really communicating, I had a physical health crisis that then caused a mental health crisis and I started spiralling as it triggered a whole bunch of abandonment stuff with from past trauma. I did a lot of unhealthy things and formed a whole bunch of unhealthy habits that were disrespectful and hurtful to her, accidentally came across an online profile for something that she wanted to be private as she didn't want to share that part of her life with me (I was upset by this because for me, a best friend is someone you'd share anything with - but I am aware I was in the wrong on this). I continued to spiral and didn't give her space she requested eventually crashed by trying to force a confrontation about why she'd been pulling back originally, why she'd been using the "grey rock" approach in any conversation we did have, demanding to know why we couldn't just talk things over and fix whatever the issue is. She then broke up with me formally as friends, told me she wanted permanent no contact, and that was that. I've tried to be respectful of this, though I will admit that in some dark / needy / remorseful moments, I've emailed her to try and extend an olive branch and she either chose not to respond or no longer uses that address - her perogative, and ultimately I should not have tried to contact her afterwards, even with no ill intentions and purely to say sorry and see where the conversation went from there.

She was the best friend I've ever had, and I hate that I fucked up the friendship, hate that my MH and spiralling got to that point and that I ruined it and hurt her and her family. I just wanted so desperately to keep the closeness of our friendship, sort out whatever had gone wrong between us, and eventually go and visit her and her family because it had been so many years since we'd hung out properly rather than playing games over Skype and Discord. It wss my fault, I hurt one of the most important people in the world to me, and it can never be fixed. All of this still floats through my had regularly about 5 years later.