You try to sow discord between them

After yesterdays shock, you are now able to think a little more clearly. There is no easy way out of this situation. Telling your mother is out of the question, after the threats your father made. Going to the police...maybe. But then you know that they'll discover some really unpleasant things about you. Besides who knows what will your father do then. No. But you have another option. Jack hates you now, but you also know that he desires you. What if you were able to convince him to keep you for himself? Then maybe they will start to fight. You think about it... It will take some time, you can't do it recklessly, because then it would surely back fire. But the idea is not too bad.

For the next few days you are behaving like an obedient slut. You take abuse and punishment without complaint, you suck Jack's dick whenever they order you to (he can now last much longer, but still he cum relatively quickly). You begin to wonder. What if you choose one of them and convince him to turn on the other? Your father made it clear that his goal is to have you for himself. You can try to convince him to do it earlier. Or you can talk about that with Jack.