Loss aversion is defined as a perception of loss that causes you to do something irrational. That person is afraid that if they let the abuser go, they will be alone. This fear of loss makes the abused unreasonable, they gamble their safety in fear of loneliness. When evaluating options illogically, one uses their emotions as a shortcut to common sense. This paralyzing fear of loss makes that person stop seeking an answer to the problem. .
A black eye, broken rib, cruel words diminishing an ego, the fear is nothing compared to the pain of their partners' absence. Not to mention the effort it will take to have to start over in life and in search of a new partner. The unknown can be overwhelming, especially when one's spirit is broken. Abused people usually can't see the debilitating damage of abuse. If this person keeps thinking that it will get better, then they are chasing the possibility of a future gain. It is really difficult for someone abused to comprehend the prospect of what they are losing, a sense of self worth gone astray, or perhaps even have been manipulated into believing that they deserve to be treated badly. This person's emotions have sabotaged their instinct. The more time that passes, the abuse seems normal. This characteristic is an innate flaw and blatant weakness. All emotional beings are in danger of its effects. The only way to avoid the fallacy of loss aversion is to know about the concept and to understand it. The mind can misinterpret loses and unreasonable treat them as gains. .
Another reason I think that people stay in abusive relationships and/or marriages is due to the moral code that they choose to follow. Those who are religious believe that God invented morality, but these emotions existed far before Moses inscribed God's list of imperatives in stone. Morality is part of the primitive brain, religion just gives people permission to tabulate these intuitions, and as Lehrer put it, "to translate the ethics of evolution into a straight-forward legal system".