This does not make them batterers. The victim actually likes it. In contrast, domestic violence takes place without any mutual trust or agreement, and is not consensual or pleasurable for the victim. A batterer's violent and coercive behaviors do not just affect the sexual relationship, but pervade other aspects of the relationship as well. A batterer may actually coerce consent to violent or dominating sexual behavior, or violate agreed upon boundaries.
Victims exaggerate the level of abuse.
If it was really that bad, they would leave. Leaving is often the hardest thing for a victim to accomplish, and is commonly harder than staying. In general, incidents of domestic violence have been found to increase in severity when a victim leaves. Leaving an abusive situation requires resources such as money, housing, transportation, and support structures, all of which may have been eroded by life with an abuser. Victims provoke the violence done to them.