Many have brothers who are not abusive. Children who witness abuse do not automatically grow up to be violent towards their partners, many completely reject the use of abusive behaviour as a result of their experiences. He's really sorry, and it won't happen again. Once a man has started to abuse his partner, it is likely to happen again. It is rarely an isolated incident, usually it is part of a pattern of controlling behaviour, which may not have been recognised as such e.g. telling her what to wear, who to see, being very possessive and jealous.
Men often say they are sorry afterwards, make promises and say they'll never do it again.
Often women who have left return to violent partners because of these promises, and there may be a 'honeymoon' period when he appears to be the perfect partner. However, most abusers will abuse again, maybe in a different form, and women should be wary of their promises. Children need a father. Children who experience domestic violence suffer emotionally and some may also be physically or sexually abused. Many women leave when they see the effects on their children of their partner's abuse.