Can it ever really change them for the better if they have that so called security? I know its not real security since divorce is so high but I was curious.
No - as a matter of fact, it can have the opposite effect. Many, many pwBPD end up divorced in the first year of marriage, causing shock to the non.
Abandonment triggers can be REAL or PERCEIVED. Trying to apply logic to BPD will not bode well for trying to understand the disorder. Focus on the facts - really read the articles and lessons, critically think about each of the traits and how they may have played out. Article 9 - 10 False beliefs, keep these in mind when you are trying to understand as well.