Without going into it too much, had a very fleeting relationship with someone who I didn't know had BPD. It was intense and disastrous, for both of us, but they would never have broken it off themselves despite it obviously having a bad effect on them as well as me. I broke it off, but months later they still can't let go. They have hospital and professional support, and could have family support if they so wished. 

This has gone so far as to end up with them constantly contacting me (and my family) and turning up at my house, me getting orders in place and sadly the police involved as I am frightened for my safety due to their behaviour. They are blaming this on their BPD.

They have since breached all orders put in place and are sending emotionally abusive content to me, mixed in with declarations of love and saying what they have to offer. 

I have been trawling this forum in an effort to understand what could be going on with them, how best to deal with them, how to try to prevent any further self destruction on their part whilst ensuring my own safety. The self destruction on their part has included breaching orders despite serious consequences, potentially risking new (very good) jobs by breaching said orders, threatening to harm themselves (safe guarding in place I believe). 

 I guess I am asking for related experiences, suggestions about my own actions, whether this does sound like actions out of their control due to their BPD? I will fully admit I do not have a thorough understanding of what they are going through, I only have an understanding of what is happening from my perspective, which seems like they are potentially throwing an awful lot away for the sakes of a very short relationship with someone who does not want to be with them now. (They have been told all of this in a clear way, I've been in no way ambiguous). 