Harassment through Phone calls & Letters

I am a married lady aged 49 Years with two children and presently working in Bangalore. My Ex boy friend who was in love with me during my post Graduation ie during 1993-94 went on till 95 and later I started avoiding him and married a person of my parent's choice from Brahmin family as I was not happy with his behaviour of asking money often as he had lost his job by arguing with the Principal and the news came in Hassan News papers also during 1995/96 not very sure about the year, So I began to avoid him he was into smoking & drinking also. I got married in 1997 and since then living with husband. He even came to my work place in 1997-98 and wrote several letters and even took Zerox of my love letters and sent to my Boss. But I ignored and didnt disclose to my Husband till now. He finally stopped writing in 1999/2000. But since October 2015 he has been calling my number as someone gave my mobile number to him. and so I atonce blocked all new numbers other than my contacts and every time I check through True Caller App who is d caller and then ignore. Each day he would call from 5-6 new mobile numbers and all the names belong to lower cadre peoplelike masons, truck owner, farmer, Laundry etc. But since four days he is calling my office also and has written a letter to me to join him as I am his wife and itseems I promised to join him after 10 years so he has been waiting and wants me now or else he would lodge a complaint against me in court / police station . He threatened me that he would die in front of my Office. Now I am terribly worried about my reputation and also about my children. Pl advice me.left me in 2000