thank you for all your advice. I have spoken to my mom and told her to delete any text messages she receives and to not take any calls from my ex. My mom said she had bad things to say about me so I can only wonder what she has been telling other people if she can tell my own mom.
is extreme jealousy a trait of BPD?
I don't think I would call it jealousy... .
From my understanding and perspective, the things that pwBPD do that affect other, positively OR negatively, generally have little to do with the particular people. My dBPDexgf cheated on me throughout our relationship; almost exclusively emotionally. It wasn't about making me feel bad or trying to hurt me, it was because she craved the attention and validation that someone thought she was worth something. Even though her actions hurt ME, they were about HER, if that makes any sense.
I would venture Your BPDex lashing out has more to do with some sort of validation for herself, rather than making an effort to hurt you. Them trying to get you away from your best friend may be because they view that person as "the reason" you guys split, or they see them as a threat for your attention. Your BPDex may just be trying to "protect her interests", even if you guys are not together anymore. And again, the reasons for this have to deal with THEMSELVES, not YOU.