Closure is something we provide to ourselves. We're never going to get it from someone else directly. Try to frame this as something you're doing for yourself. It's not about him making amends, it's about you realizing what you need and looking for something better.
He is incapable of a healthy attachment and a consistent loving relationship and he knows it. He hates it but he knows it. He is very respectful while discussing the end of us and dividing our things etc. He said it sucks for him because he doesn't want this to end but respects my decision and gets why I am breaking things off.
Who's to say that he is incapable? There are lots people with personality disorders that reach remission from symptoms. I think that this is an important thing to realize. We can't blame our pwBPD for everything and wash our hands clean. That's not how relationships work. We act and react, and so do they... .which means that we have some soul searching to do in a lot of cases.
It'd be impossible to say what his motivations are for being kind. Maybe he actually does respect your decision. Either way, you're leaving. So why question his behavior?
