Marriage and divorce

I'm 37yrs old and legally divorced. After 8 yrs I meet a girl and got married in church with both families however our marriage is not legally registered and that girl had a broken marriage(separated form her first husband) but not legally divorced. We have one girl child however she already had a girl child for her ex husband. As days went on I found her being unfaithful to me. She had a lot of boy friends and was going out with them. I have spoken to her about this and she always denies that she making a mistake and hasn't stopped. I'm fed up and decided to stay with her for the sake of my daughter but was not willing to be her husband anymore. I started to hate her. Later I met her younger sister and we became best friends but as days went on I realised that I was falling in love with her. She had a broken living relationship. Later we both understood that we have are attracted to each other and can't avoid the relationship. My wife and her parents came to know about my relationship with younger daughter and treated me every bad, I explained everything that happened between me and my wife(even her mom knows everything about her first daughter) they deny that she is not cheating me and kept threatening me that they will give police complaints on me and their younger daughter. It's been a year since I have moved away form my wife and that house but I can't forget or avoid the younger girl(same with her). After my wife came to know about my relationship with her younger sister she became very furious and started to hit me abuse me and her sister.(several occasions these arguments turned horrible). Now I don't want to live her anymore. I want to legally divorce her and legal register my marriage with that girl. Also we need permission to see my daughter even after divorce. Please help.