Boyfriend is harrasing my family

I was in a relatuon with a boy from last 5 years. I used to completely trust him. I use to live in hostel. We decide to go for a secret marriage but he fooled me by taking my sign in a simple notary and told me that we are now married and can have physical relation.( I was not having much detail about marriage process). I believed it to be a real marriage and indulge in physical relation many times . After 2 year one day I show the paper to my hostel mate they told me that this is simple notary and it is invalid. From that time i start realising that there is something wrong . But i didnot focus in that matter and was living usually but one day he demanded 5 lakh rupees from me to start a business and threaten to blackmail me. When I try to avoid him he started putting wrong allegation on my charachter. I use to share my fb passwrd with him he start misusing it and posted all my photos and marriage proof in facebook. My parent got to know this they bring me back home and supported me a lot. There i got to know he used to record all our talks where i was saying if my parent will not agree we will break all relation with them.. He always used to be in conference whenever i talk with my family he has recorded each and everything. He uses my fb accnt to tlk to boys and blamed me to be a charachterless. Today he posted my nude pik on fb my family is not that much finacially strong to afford court thats why i m very much depressed . Please suggest me what to do.