Abusers are addicted to violence. Abusers make choices about how to behave in their intimate relationships, choices that are supported by societal attitudes of male privilege and lack of accountability. If victims didn't have low self-esteem, they'd leave. Lowered self-esteem is a frequent outcome of victimization and is often exacerbated by secondary victimization from potential sources of help. Victims come from families in which their mothers were victimized.
Violence is perpetrated by one person against the other.