I seek advice,how i can save me,my family and get divorce

I am from west bengal, got married on 26/10/2012. before marriage i had physical relation with my partner. my marriage is done in special marriage act. my marriage has happend in strange way. but that seems to be saving me and my family.i got my first job in 3.07.12 and joined in indore on 16.07.12 then i shifted to nashik till i left my job in octobor 15,2012.i had wish i will mary her,but as time goes on i feel she is very dangerous,and cheating me(i got informed that she had sex with other people also).so i change my mind.but my girl friend threatning me,and force me to sign in marriage registry. marriage register was person known to her family, so they together made a conspiracy. without consulting me they give a notice date(on 12.09.12), on that day i was in lavasa(pune) for my job purpose.i came to know of all this things much after,and on 26.10.2012 my girl friend with his relative force me to sign on registry paper in one of her relative's house,where i used to go some time.they presented 3 witness her aunty, maternal uncle, and one her relative's neighbour(i already came back from nasik on 17th oct,2012). after that i was really shocked,didn't know where to go,as i knew nothing about law. also parents were not in mood to accept my girl friend,i didn't bring the issue. after registry happened, she started to mis-beheave with me,talk to me in rough language.as her only motive was to trap me and get money from me whole life-time,and to had sex with another guy(who i don't know,but very sure about it). i started concentrate on my studies and govt job preparation,and after marriage we never had any conjugal relation,and we never stayed together. i didn't contact for almost last 2 years. but recently it becomes a headache,because i heard she is planning for some litigation against me or my family also. so ,i want to know what are the legal issues,by which she can harrsse me ,how to get rid of all this things.