The usual response to these situations were to disappear. Unfortunately Bella had realized that even when she chose to stay that people forgot she was there. How was it that she could be so important to someone and then so expendable.
It was recurring theme in her life, first implemented by people she should have been able to rely on. In a totally common societal cycle, she carried this throughout her life. She had unconsciously let it weigh in in her decisions in life especially in regards to searching for a partner.
Like everyone else on the planet she longed to be wanted and to belong. But after years of rejection on both fronts and the crumbling familial base, she was scared to pursue anything outside what she knew.
Anything she felt that was too good for her.
So here she was in another situation with another person who went from finding her to be treasure to hoping that the trash would take itself out.