Someone is trying to blackmail and blame

I am a student and my age is only 17 Years. When I was at the age of around 12-13 years, I talk to my tution teacher through texting her just normal conversation but her husband took it as a opportunity and started fight between him and her wife because the relationship of husband and wife are not good, husband wants divorce but she is not agree with it. After all he is threating me as I would file rape case against you and told to everyone that you and my wife are cheating on me. And now also he give me threat I will blamed you if my wife sucide because of our fights and I will also blamed you and my wife are in extra marital affair. I am a student if anything like this happened me and my future, family, reputation everything will be destroy. I want you to suggest me what should I do so that I can protect myself in future if anything happens. ( I don't want to take any action or file case against him, I just want to protect myself if anything happens in the future like this ) So, I kindly request you to help me by providing any report or complaint copy so that I can protect myself in future.