boyfriend for 8yrs, stayed together as hsband wife too dnying to marry

My boyfriend for 8yrs promised me for marriage(have chats proofs),even stayed together for a month as live in couple(have every proof) I accepted him as my husband mentally,now denying for marriage as we fought over something. His family doesn't know anything, can I do something legally so that he can marry me? Also he cheated on me and slept with a prostitute. Can I file case against him? Is there any way to force him to marry me? My family knows everything and they doesn't want to loose reputation in society because of this. They're saying to marry him. Even I too want to marry him only after everything. I feel like i'm mentally,physically,emotionally harassed by him even tried to commit suicide.I have every proof of this relationship like chats pictures call records. But I have threatened him that I'm going to destroy his reputation if he isn't going to marry me. How can I do something legally so that he will marry me legally?