Wife of Colleague physically abusing and harassing me and my family

My colleague has been married for 20years and has a child of 15 years. They've not had a harmonious marriage since the beginning. For a year my colleague and I have been seeing each other and we would like to get married.The wife doesn't want to divorce him simply because he will be with someone else. She and her family and child physically and verbally abuse him (which I've heard over phone calls and have recordings of the same). She stretched it to the extent of coming to my home and beating me (CC came footage is there), and de-faming me and my family in the neighboorhood. She has threatened to kill him and blame me for the same. She and her child have record of our photos and whatsapp texts. How can I protect myself from this woman? My family is against me taking help of local police due to family dignity. How can he apply for divorce? This issue is affecting our careers seriously.