Flase accusation

Hello there, For the past two weeks there is this person who has been harassing me and trying to extort money from me because i slept with his girlfriend, now the sleeping part was with mutual consent and i even dropped her home the next day. On the same day i get a call from this person asking me if something happened with me and her, she had told me not to say anything to her, i abided and said nothing to him, later she was forced by this guy to tell her the truth and she cracked and told him everything( he pressurized her into admitting it or else he would tell her parents everything) now this guy has made my life hell, he called me after 4 days and said i'm giving you two options here : -1. give me 1,00,000 INR and it will be the end of it 2. Go to jail (he will make her lay false accusations of physically assaulting her and rape charges) now when i asked the girl what is she going to do she said to me i don't know. I was perplexed with her answer and now this guy has given me 3 days time to gibe him the money or face the consequences. I've a recording of him asking for money here). What can i do here and i don't want any more of this crap in my life now, tell me what should be my next move here.