Blackmail, perhaps, to put the final nail in the coffin and drive him away from you completely. Or something to prove that he's as bad as you think he might be, that your gut tells you he must be.

Or, just maybe, something that proves he isn't.

Oh- but we can't be having that of course. If we start believing people who say they want the best for us, who knows what sort of dangerous slopes that might lead to? God forbid, you might even start to want him in your life.