if he is an abuser, you dont tell him. you save the little bit of money you have, hide it. you get stuff packed when he is not around and bring it to a friends or parents home. you can apply for rental assistance, medical care and food. those you would get right away but rental may take 3-6 months.
you file when you are ready to move. its never good to file while you live w him in abuse cases, and also make sure the server knows hes abuses you. you dont have to put your address, put a friends so he cant come hurt you or stalk. you will have a temp hearing so you dont have to worry about kids not seeing him till then. thats all decided that day.
you probably can also get a lawyer for free in abuse cases. just call the local shelter and they can help you.