Insecure

i met a guy after i joined a s/w firm. the guy was very good in nature and v had become very close friends. but after few months v did not find much understanding between us. after a year my parents had seen a alliance for me.He is my relative so v started talking to know abt each other before marraige. my office friend did not like as he was possessive. i told him dat as am engaged i wil not be coming out with him anywhere.. he got so much angry for this and kept fighting with me. one day i had gone to movie with my col best friend for the last time before my marriage. my friend knew about dat and started fighting again. now am not able to talk prop with my wouldbe. he is not allowing me to talk prop with my wouldbe. he is threatening me dat if i dont talk with him he would say something wrong abt me to my would be.am not able to get rid of him now and am scared dat it would affect my marriage.