Is it really Out of Sight, Out of Mind?

Just wondering as my ex broke up with me a month and a half ago through text, there was no fighting, just a lot of confusion and I really didnt get closure (I know its not something we always get) but she seemed to backtrack a little bit but after I sent a few texts expressing my love and asking if she wanted to move on to let me know and Id stop bothering her, she just ignored and went silent. Im just wondering if a person can seriously just forget another so quickly even when a room can be littered with mementos of our relationship? I treated her like royalty and never argued or fought with her. Just curious for a BPDs perspective.