Welcome Carl!
Since this is the 'detaching' board, I assume you do not want to get back together with your ex? If you do have hopes of reuniting, the 'saving' or 'improving' board would get you more pertinent advice

I think most of us here on the detaching board find the best way to deal with our exBPD's is to not deal with them at all :'( I honestly do not think there is much we can do to help them. Obviously we tried during the relationship and it didn't work out. One of the factors that determines a personality disorder is the inability of the sufferer to acknowledge that they have a problem. Sadly, you exBPD will likely never be able to accept the diagnosis. You must have a very kind and compassionate soul to want to help him!
Maybe it is time you focused on YOU and what you can do to help yourself? How are you feeling? How are you dealing with your break up? What are you doing to heal and grow from the experience?
This is a wonderful place filled with kind, helpful people. I look forward to hearing more of you story.