Wife's extra marital affair

Hi, My wife is having an affair with her one of a relatives. He is her Jijaji in relation. She is having affair with him probably since 3-4 years. I was not too sure about their relationship as of now, henve didn't pay any attention towards my wife's behavior. The day I started questioning her, she left my house and moved to her parental home. She is still in relationship with that guy. I have also come to know that, that guy is a Lawyer and now my wife is misusing the law to dominate me and my family. She has filed 498a and 125 for maintenance. I want to get divorce because my life is at risk now. Please help me what should I do and how should I process in this case. Thank you.