Sorry to hear you're going through this
First, you didn't do anything to cause this. He was broken long before you and he will be broken long after. As hard as it is, you can't compare his new r/s to yours. It's not that the next person has the crabby patty formula that makes them 'better'. They are in the idealization phase and that's different lengths for different reasons. But, there's one constant in this formula: it will fail, in time. It always does.
Did he control his behavior in the beginning? Sort of. PwBPD don't have an endgame. They don't set out to harm you. Those with N traits sometimes do, but I'm speaking solely from a BPD standpoint. You'll beat yourself up asking "was any of it real" and "did I ever matter" and so on. The short, simple answer is: yes. Yes, you were loved. Yes, you mattered. Yes, it was real. It all was right up until the moment that it wasn't. And it happens that fast. They love you with every fiber of their being right up until they don't. And we can't do anything to change/stop that.
As Blue said, none of this was about you. It was always about them. You were the answer, their savior... ."the one". Then, you weren't because you weren't perfect... .the answer to all their problems (hint: no one is!).
What's important now is that you take care of the only person you're responsible for: you.  :)o you have a good support system? Have you talked to your family/friends about your wishes to not hear about his life? Have you sought professional help during this difficult time? Breaking a trauma bond is difficult. Trust me, I know.
Keep posting
