WHY DOES MY MIND KEEP RRMINDING ME OF ONly the good times we had together ? Why is it portraying my ex as an angel and me as the counterpart. ... .
Often the most intense feelings, the ones that are hard to comprehend, are buried deep in our family of origin experiences. Unresolved grief and deep feelings go underground and gain strength. Our pwBPD bring those feelings to the surface. They may trigger the original wound and because we have suppressed those feelings, we cannot easily see their origin.
If you experienced a significant loss when you were a child, that may help guide you to those original feelings. Some adults do not have the skills needed to help a child grieve. Your family wants you to get over your ex quickly, with a snap of the finger. Perhaps they were the same growing up? Your feelings were dismissed?
It's worth looking at these early stories and trying to reprocess the feelings. That helps you get centered so that you can be the emotionally stable person in whatever relationship comes next, BPD or otherwise.