Can a married man and a married lady stay with each other without getting divorce ?

KD was married to a beautiful girl named CD in 1998. They had two sons. But from the very beginning both KD and CD fought with each other. KD had beats his wife every night. Used to drink a lot and created problem. After 19 years of marriage, in the year 2015 KD stopped giving money to his wife CD and went away leaving his wife with two sons. Then CD used to work hard (tution + a job in private company) and stay with his two sons, taking the total responsibility of the family. In 2017 CD filed a case (domestic violence) against KD. Now she stays with her sons alone. There is a gentleman named Raj who is also married but stays away from his wife for years. Raj used to stay nearby area of CD. Raj used to help CD and his two sons from the day KD left CD and her two sons. Now in 2018 they (both Raj and CD) thinks that they are in love and want to stay with each other. My questions:- 1). Can both stays together without having divorce ? 2).Can both stay in living relationship ? 3) Is living relationship legal ? 4) If no body complains about living relationship, then will police do anything ? 5) Can CD and Raj stay together in same flat ? 6) What problem will both Raj and CD face if KD files a case ? 7) CD had already files a case against KD for domestic violence. They both stays in different cities for 2 years. Is it, that the marriage registration gets cancelled as they dose not stay together for 2 years ?