I sued my batterer in court. It's all about evidence. From the moment you, or your child, or your pet, is first abused, if you are stuck in the relationship because of marriage, children, finances, religion: Start collecting evidence right away: Anything you can use to protect yourself when it becomes your word against the abuser's will be critical.
Pictures of bruises, etc., threatening texts, nasty voice-mails, emails, anything and everything. Keep these in a safe place along with your keys and money. Then get out the best way you can. You have to fight with everything to get away from these people. Use every resource at your disposal.
Don't be silent and don't be passive. Don't give up. There are many resources available right now to help you.