How can i file harassment if I am guilty of something too?

Hello. I am facing harrassment from my ex boyfriend. He has information about me stealing (unfortunately it is true) from my job. I have not stole anything recently, but i did in the past. He is using that against me threatening me that he will go tell my job about my history with stealing and he said he has proof. Im not really sure of this, but i know if he goes there they could check the cameras. He also knows how i steal and can tell them. He has possession of my iphone and his close friend told me he has it but to my father, my mother, and everyone else he is saying he doesn't have it. I think (I know) he is lying. He claims he threw it out the window in his back yard but we were unable to fin it after looking countless times. I know I am guilty of stealing, but is there anything I can do to file against him?