Divorce

My wife has love affair before marriage and after happening of our marriage with in one week I came to know that she had an affair because of her behavior with me. After that I have found some photos which they both have taken in hotel room and some selfies on different places. Also found some messages of her in facebook explaining to other person what they both had done previously. After knowing all this also I tried to live with her but when ever we have small issues and disturbances she used to blackmail be that she will commit suicide. Also I assume that she is still in contact with that person. So on what basis I need to apply for divorce.Now she is not ready to give me divorce. Also most of the times she will deny to have sex with me. I am very much frustrated because of all these things. And I am living single from last 5months. Can I apply for divorce before one year of marriage because marriage happened on April 2017. When can I apply and on what grounds..if she rejects to give divorce what shall I do..and how many years it may happen to get divorced with her.