One school of thought is that domestic or intimate partner violence is due to a need for power and control on the part of one person over the other. Most often it is the man over a woman but the reverse can be true. As well, domestic violence is also seen in same sex partnerships. That would lead us to conclude that the issue is not a gender issue but rather a relationship issue.
There can be a number of factors that lead an individual to need to dominate in a relationship. It could be that as a child it is the only dynamic they saw between their parents and therefore think that abusive power and control is normal. It could be due to deep-seated feelings of inadequacy that demand control over every aspect of life to maintain their sense of self. Whatever the reason, it is unhealthy and unacceptable.