Need legal advice

I am Sunitha Sharma from Mumbai. A year ago I had an extra marital affair with somene I loved in my college days. Now I am out of it. But the wife of Prem had seen all the online chats (including s*x chat )on Prems computer and has the secret phone bills that we used. Though Prem and I are not in a relationship now, she (wife of Prem) has been threatening me over phone almost every couple of days that she would disclose this affair to my husband, children and my parents and put me to shame. She has been sending me threatening messages that she would die and is cursing me and my children every couple of days. This is affecting me psychologically. I am not able to concentrate on my work and am pained mentally living in fear. I know I made a mistake and I am out of the affair now. Kindly let me know if there is any solution to this problem legally with appropriate sections.