Why couldn't she be happy with me?
Because it was
your path to become the person you are today, not hers. Her path is different, and she doesn't "match" with you anymore. I believe that we attract people into our lives to learn and grow—you've done that with your ex., and your purpose for being together has been fulfilled.
If she seems happy with her new partner, be happy for her if you can. BPD is such a difficult hand to be dealt, any pause in the suffering is a blessing, right? And no one can get inside the heads and hearts of anyone else. Appearances never tell the whole story, BPD or not.
Your job is to enjoy the fruits of your hard work and keep growing in joy, willtimeheal. Congrats on building a new life and thriving!

heartandwhole