My wife is mentally harassing me and not letting me see my son

I am in an 8 year marriage with my wife. We have a 4 year old boy. Since the past 1 year she has moved to her mom's place and not coming back. The reason was because I was involved with someone else in 2017 (not physically) and I stopped in 3 months the same before she even knew about it. However, this came into light and she got to know in 2019. I have apologized too but she has insulted me and my family abused me and family and hit me too. She has taken my child away and now the situation is such that she is not letting me see him or talk to him and has blocked me and my family everywhere so we can't speak to him It's been more than a year and she has been mentally harassing me and my family even though we have been nothing but nice to her. She has been teaching him things so he can forget his father and grandparents. I have all the messages and communication of her abusing and disrespecting me and my family for more than a year. She and her mother have mentally and emotionally abused me. Request you to please help me with a solution where I can be with my child or because this mental harassment I might end up doing something wrong to myself. PLEASE HELP!!!