Does the BPD person miss the discarded partner if the BPD person found a new relationship?

My partner of 2.5 years was very emotionally stable. Almost to a fault as he would not talk about his feelings too much, even when made known it’s a safe space. He was very secure in himself and the relationship. Fall of last year he went into an episode which I thought was bipolar mania with psychosis (per hospital) but due to dysfunctional family I didn’t get much information. Lately I am thinking he may have had BPD in addition to the bipolar mania.

I was discarded September, he called me in November to talk but wasn’t in his right head. I told him even if we’re not romantic anymore I still love him and forgive him.

December he flew his ex in from Brazil and married her.

March he jumped out of the window and killed himself.

I really just have so many unanswered questions and I had been suppressing the questions but lately my mind is flooded.

-did he miss me? Did he value me after that? -can BPD just show out of nowhere? -what was the ex thinking? Who in their right minds marries someone in the span of a month -why did he kill himself