A person who feels they have no power or control in their life may use the tool of physical, mental/emotional or sexual abuse to regain some sense of power. The home and family is perceived as a "safe" place for this, whereas at work they may feel impotent and manipulated themselves.
It is shocking that half of American women have suffered physical or sexual abuse in their lives - and 15% of men. One third of pregnant women are physically abused during their pregnancy, in the USA.
The issue of self-esteem and the effort to improve it through personal growth is not self-pandering or only interesting for wimps. It's central to happiness for adults, children and families. If people don't feel good about themselves, if they can't express their feelings and work toward accomplishing their real needs and goals, they will suffer and they will often make others suffer too.
Emotional charge builds until the point where control breaks down and irrational, uncompassionate behavior follows. Charge is emotional frustration, based on judgment of rightness, wrongness or appropriateness. It is resistance to what is, in other words a lack of acceptance. And the real, underlying factor is always fear: relating to basic needs for survival, safety, belonging, affection, control, certainty, achievement, respect, and so on.
(Note: to break this cycle it helps to spot and reassess irrational beliefs that obscure one's view of objective reality and that reinforce the anxiety. Most of us need some help with this, either from a good therapist or if we feel capable, by using effective personal development tools.)
The people on the receiving end of abuse may also have a big black hole of emotional need, so they accept the abuse. At least it is attention, at least it is a feeling. And to fill their unmet needs they turn to food and other addictions, drink, drugs, cigarettes, manipulative sex, etc. And they abuse others in turn, including the easiest victims, the kids, or others in their care.
People with destroyed self-esteem end up believing they deserve what they're getting; they become brainwashed through intimidation, threats and invalidation. You see the same thing in the military, in cults, even in school.
We each have a personal responsibility to improve this state of affairs, starting with ourselves and our own families. There are some important aspects of behavior that you can teach your kids by example, which will be invaluable for their future lives.
What advantage is it to send a young person out into the world with a head full of knowledge but without the confidence to use it effectively, or the ability to grapple with life's problems with that inner stability and optimism that alone can bring success?
The most important thing your child can learn is that you love them unconditionally, without judgment. That is the rock on which their self-assurance will be built. We need to demonstrate that love by listening, genuinely listening, to our children. By never imposing our own evaluations, instead asking appropriate questions to guide the child to see objectively for themselves. And never making the child wrong when they give their opinions or make mistakes, and try to discover their own unique identity.
Secondly, a child (and each of us) needs to learn that we create our emotional responses based on our interpretation of things. No one "makes me angry" - I make myself angry based on the way I choose to look at things. That is usually highly influenced by the way I have been taught to look at things, especially by my parents, so if we hope for our children to be emotionally intelligent, we need to be ourselves, and we need to base that intelligence on a world view that is open minded and flexible, based on facts and observation, not prejudice and our own cultural conditioning.
It takes time and experience for a child to learn to understand and control their emotions, and to take responsibility for their beliefs, their reactions and behaviors. For this they need guidance and a good example. You.
Adults are children with more experience. Children are adults with less experience. Both deserve respect accordingly.