Hi DenseFog and welcome to the forums... glad you found us and were ready to share some of what you are going through. Your situation sounds excruciatingly painful and I'm sorry it is so difficult right now  

The advice you're getting online... Is that advice on how to reconnect with your partner? Or how to end the relationship? 
As far as you can tell, do you want to reconnect in the relationship? (I think I was reading correctly that your partner initiated this latest breakup, please correct me if I misread that).
BPD relationships can often take unintuitive skills and tools, and can require us to have extra support, extra skills, extra sense of self, and extra emotional grounding. None of those are bad things -- they're great things! -- and, it can take some time and practice to get ourselves strong, stable, and skilled, in order to have a more effective, "less bad", more livable relationship.
So, let us know if reconnection is what you are thinking, and we can work with you. Of course, we do have other boards for if you are conflicted about the relationship, or if you are detaching and ending the relationship. All the boards have different focuses, so we just want to make sure you are on the one best suited to your goals.
Please feel free to post and share more, whenever you feel ready...
kells76