Hi Ananta,
Welcome
I wanted to join foody in saying hello. There are many thousands of people who come through here with very similar stories, the details may be different but the emotional and psychological effects are the same.
Did you end the relationship with him? Any kids involved?
What behaviors lead you to think BPD is in play here? A lot of people here have partners or exes who are sub-clinical, it's often hard to know for sure because the process requires some degree of cooperation and that can be difficult to get from someone who has limited willingness or capacity to take responsibility for their actions.
How long have you been separated? Have you been through a cycle like this before?