If you wonder “why she stays” or “why he hits” it is all the same. It is all about power. They both feel powerless.
She doesn’t leave because she thinks she can’t support herself without him. He makes all the money. He knows how to repair the cars and the house. But also he feels powerless. If he doesn’t have her then how is he going to get fed? How is his laundry going to get done? They stay together out of a sense of desperation and powerlessness.
If you want to address the cause of men hitting women and women taking the abuse, you have to address the root of power. You have to teach boys how to cook and clean and take care of the household in addition to teaching him how to use tools and repair cars. If you want to teach women to be strong you have to teach them how to use tools and how to repair cars in addition to teaching them how to cook and clean and take care of the household. Only when there’s a sense of equality will there not be a sense of powerlessness.
Men also abuse others because they have not been taught any other way to deal with their emotions. “Boys don’t cry”, remember? Boys are taught to roughhouse and to fight. They are taught to be aggressive. Anything less than this is seen as weak. If a guy shows any gentle tendencies he is seen as gay. He is excluded from the pack. Thus when guys feel powerless, they will lash out with the only tool they are allowed to use and that is violence.
Part of power is also about giving people a sense of worth and value. They have to feel like they can take care of themselves. This includes being able to get and keep a job. People need to feel like they are needed.
Address these issues and you have solved the reasons why he hits, and why she stays. Teach people how to be independent.