He's 19, not a child, and doesn't have any excuse for this. Obviously, he can't want this baby too much or he wouldn't risk the baby's life (or yours) by hurting you. At 15, you need to get away from him. What do your parents think? Or, do you hide it from them? If so, that's the worst thing in the world you can do. It gives him a cover to hide under when his crime should be exposed. He'll be a whole lot more likely to change, if not for your sake, for his and his child's, if everyone knows what he's doing and give him hell about it. That includes his family, your family, and all your/his friends. I'd put him in jail if you were my daughter.