Can i book a case on my boyfriend who is married to my cousin sister and used me too sexually ?

Sir, i am i and my boyfriend are in a relationship since 6 years. I was in a relationship with a man inspite of knowing that he is married to my cousin sister and had kids. The relationship between my cousin sister and her husband was not good as my cousin sis was having affair before marriage also and after marriage also. 6 years back, when he asked me to start up a relationship with him, i was aware of the troubles given by my cousin sis to her husband. as i came to knew everything about the torture and hellness in their relationshp, even i accepted his proposal. when my cousin sis's husband and i started our relationship and and as i was still studying, we had a sex on the promise of marriage after completing my education. inn the middle of that my cousin sis's parents expired. my boyfriend never cheated his wife my cousin sister). he told me that he will never leave my hand and even his wife hand. we had completed 2 years of our relationship then i was caught from my parents when i went to meet him. their my parents my uncles threatened my boyfriend, next day my uncle went to his place kidnapped him, he left some people and half murdered my boyfriend. as i came to know about half murdering my boyfriend, i contacted again to my bf and again we both continued our relationship till now. again after 3 and a half years, my cousin sis came to knew about mine and her husband's relationship. my cousin sis called my parents, she informed my parents about our relationship and again my parents threatened me that they will kill me and my boyfriend also if we continue our relationship again.since 2 months, my boyfriend has not contacted me. i dont know where he is. i contacted my bf's elder brother who lives in singapore to me him to contact me. he was telling ok ok ok for many days and till now he did not made him to contact me. if i travel to his place to file a complaint, my parents and my uncles may kidnap me from on the way or kill me. i dont know what to do. my parents are makinf me to marry forcefully to another guy according to their will and wish. i am not a prostitute to have a sex with some guy and marry some guy.i feel that he have decided to leave my hand as he have not contact me since 2 months. i dont know on what matter basis should i file a complaint on my family and my boyfriend. if i did not get any solution, i have no other option but to commit suicide. i need help to get me justice, please help me...