i can see that u only concern is that the price to pay if u break up with him.
i wonder what does he have, against u. photos, videos ? i am refering to the things that he is using to threaten u should you break up with him.
well just report to the police, if u don't want to blow things up, tell your father.
tell him what happen, and nth but the truth. i am sure your father is a bigger pai kia than your b/f who is a 17yr kid ? i am sure your father can settle things with him.

rmb by telling your father the truth, what he can use against u is all now useless.