I believe in owning up to my BPD so I try to regulate my reactions by expecting things to go in the worst direction possible and prepare myself.  

An example of this would be when my boyfriend (now fiance) and I were discussing getting married and him buying a ring.  At first, he seemed really excited and ready to buy a ring. Three months later, he was still talking about it but he still wasn't pulling the trigger.  In my mind, I already had put the idea in place for myself  that  A. He wouldn't ever get me the ring, B. That he would get me a ring I hate, or C. He would wait so long that I would end up resenting him for not proposing sooner and destroy our relationship with my splitting. 

I do this in my mind naturally anyways but I INTENTIONALLY do it as a way to expect the worst and learn how to manage the feelings before it happens. It helps me to feel prepared even though it may prematurely upset me.  This way, I end up having either no mental/emotional explosion or a muted one. 

Does anyone else have experience with this? Is it unhealthy to anticipate catastrophe or healthy to be prepared for it?