Wife cheating & threatening to file false case of dowry harassment

My wife left my house when i was in office on simple fight on phone. She previously also did this. I married on 9th Feb 2014. She lived with me for 40 days and after then she left. We tried many times to get her back but she did not come back. After one year, my parents took her and again she went to her home in a week time. Recently, in August, 2016, on my request she came and lived for 2 weeks and again left. she repeatedly threaten me that she will file dowry harassment case. She also threaten to kill me or kill herself. I did not know where she is. Her family members also did not tell her whereabouts. Recently i found a facebook post where she is with another boy. i tried to contact her family members but there is no response. I went to her home where i did not find her. I was told she is doing job in Bangalore. Her brother attacked me with knife and threaten me to send to jail. what can i do now?