A man is designed as a dominating human machine more like a ruling kind. Since a man feels in charge, anything or anyone who challenges that aspect becomes a threat, provoking him to retaliate just to protect that man ego. Many men are robed of this manly element while still children usually by being bullied and so on.
When tormented and bullied boys grow into men they tend to become abusive with an intention of demanding for respect, subconsciously trying to restore what was taken from him while a child. You would find that in relationships men who are trying to restore back their ego end up killing their spouses just because they wanted to end the relationships.
When a woman tries to leave a man who demands respect, a man feels like his ego booster is trying to escape. Feeling threatened drives a man to rather lose the woman that having the idea of someone else having her because without her he actually feels powerless.