Hmmm. On the one hand, if you lost trust in him and he feels you're stuck, it's only responsible to try to refer you to someone else. On the other hand, It seems quite irresponsible to make promises to never abandon you. Even if he can take absolutely everything you throw at him, which doesn't seem to be the case, there still might be situations where he has no choice. Starting fresh and building trust sounds good, but does he actually have an idea how to? I don't get the sense that he really knows what he's doing. Would it be an option to start seeing a 2nd therapist to either help stabilising the current relationship, or to help to come out of it without feeling abandoned?

I'm saying this because I had a very bad experience with my ex-T - I also have a BPD diagnosis, and ... she didn't try to terminate me, but the situation became unbearable enough that I did (sorry if that's too vague, hard to find the balance between that and derailing the topic ... it was very messy). I was also crazy attached, and even now, well over a year later, the attachment stuff is really difficult to deal with. One idea I had back when still trying to fix things with xT was to involve an outside therapist. I did not pursue the idea then, but after I started working with my current T, I couldn't help but think that if I found and started working with her back then, it could have led to at least a smoother termination with a possibility to work out lingering attachment issues.