Boyfriend blackmailing about private pictures

I was in a relationship with a guy and he always used to force me to have sex and send me nudes.If not, he used to stop talking to me. Since I was deeply in love with him,I sent him 2-3 private pictures. But day by day he started ignoring me and I felt really bad and he always accused me of cheating when I was talking or texting my classmates who are guys. I have never cheated him. He has huge trust issues and I couldn't bare him any longer and asked for a break up. During our relationship, we had sex thrice which he actually forced me to have,otherwise, he said that he would leave me. After I asked for break up, he texted me saying that he wants to get back to me otherwise he would post the private pictures on the web with my personal information like my phone number,address,parent's ph no. He is a certified ethical hacker so I was frightened by his behavior. I am not at all interested in getting into relationship with him. So, he said that he wouldn't post my pictures on the web on one condition. His condition was to treat him as boyfriend for 6 months and have sex with him for 2 times and only then he would leave me. I said okay and has sex with him once. I dont even understand what I can do with my life. He says that it's the punishment for me as I have cheated him by my words that I said that I would be his wife and all. I didnt knew his evil behaviour back then. I cant say this to my parents or anyone because it is a conservative society and I would be left alone. What should I do now?