The event that ended the relationship was: I was talking to her nice (edit: male) roommate about politics or something at about midnight while she went to bed apparently in a good mood. Turns out that was unacceptable, and she came back out of her room 20 minutes later, started berating me for it while I was confused, escalated to shouting at me for an hour while I remained calm, and finally threatened to call the cops on me. I walked a couple miles home at 2 AM through a snowstorm, while she sent me 10 desperate text messages. I never talked to her again, though I spent months agonizing about it (to the point of panic attacks), because I felt guilty that she desperately needed help and I thought I might be able to help her through continuing to patiently and reliably engage with her (it didn’t seem like anyone else was around to help her), and I liked and respected her as a person, but decided I couldn’t take it for my own mental health.

We only dated for a relatively short time, but it took me a move across the country and a year to sort out my feelings and start dating again.

YMMV.

Had a pretty similar relationship. I was the one that wanted to get back together though. But this one time he didn't apologize and did the most incredible 180 on me. Never felt so hated, almost killed myself [0]. I tried to engage once in a while, sometimes he would too. But would never act/talk "normal" again. He found a new bf and talked about how much he loved him just to make me sad [1]. And one day just minutes after insulting me all of a sudden he starts talking like the old him again. Wanted to meet up. Was so happy. He wanted to just hook up tho, not into that, but still I wouldn't outright say know, was very happy to meet him anyways. I tried saying something like "lets go eat something and we'll see what happens", but he snapped and started berating me again. And that was the final end of us, never messaged him again and neither did he.

[0] which what made me start reading about BPD [1] he'd either talk about this or berate me, wouldn't mention anything else, work or anything. We were always super chatty about literally everything so yea

FYI you're responding to a borderline on a throwaway. Don't waste your time.

Don't you think calling out somebody as having BPD based on a couple comments discredits your BPD anecdote somewhat?

For those taking notes, your girlfriend may respond negatively to going to bed alone while you have one-on-one time with her friend or roommate (or any other woman) late at night, especially if the other is being "nice."

Yes, it’s reasonable and entirely within the realm of normal human feelings to not want to go to bed alone while your boyfriend continues a conversation with your male roommate. It is reasonable and normal to feel upset that this desire wasn’t implicitly obvious to your boyfriend.

But the typical response to a minor misunderstanding like that is to make the communication more explicit with a simple request that the boyfriend come to bed and share that you felt upset about it, trusting that your caring boyfriend will feel sorry, make a note and try to do better next time. Not to lead with accusations of ill intent and quickly escalate to a full range of emotional manipulation and threats of physical violence.

Maybe you just need to know better people.