Husband cheating while staying separate

Hi, I have been married for 14 years now and have a 11 year old son. I walked out of his home 7 years back when I couldnt get along with his parents and he wasnt ready to live separately with him. He would come and see me and my son on weekends. But as my son was getting confused with this arrangement, I stopped him from seeing his son on weekends too. I hoped that he would miss us and moved back to us and set up a home but he didnt. He begged me to come and stay with his parents home. One day I threatened him to give divorce and he came to me running to my home and stayed for 1.6 years. But later his dad expired so left to his parents home again to be with his mom. He started again to beg me to return home but I never did as he was living on his mom's money and earned little and wasted all money he earned and never spent on me or my kid. But he still wanted me to stay and would daily beg me. I trusted that he loves me but unable to set up a home because he was incapable of earning money. I have not met him for the past 2 years though we talk on whats app and update about son. But I wont let him meet my son because my son is getting confused with a weeked dad.
Suddenly last month, I came to know that my husband was in a full-fledged affair for the past 6 years - even while he was begging me to come and live with him! WOW! When I confronted him through messages and calls. He denied it first and then bluffed that it was phone sex and then said it was just one year old affair. But from what I read and pics I saw, it was a very long and deep affair and he said they broke up months ago. I dont believe any of these stories and as I dont stay with him anyway, I have no chance to spy on him remotely. Im totally shocked that he cheated on me while begging me to come back to him. While I was waiting for him to change his mind and come back to me, he was busy doing all these. I asked for a divorce but he flatly denied giving one and begged for forgiveness. But I dont know how we can try to reconcile when we both dont even live together?
Its impossible for me to leave my old parents and go and stay with him in his house with him and his mom that too after leaving his home for 7 years and after this affair.
My parents and family are very angry with the affair and wanted to disclose this to his mom but she is too old to bear this at this age.
He is not even ready to completely come clean with the affair or attend counselling. Im sure in counselling they would ask us to stay together but we cant as he cant leave is very old ailing mom alone and stay with me and I cant leave my own parents and live with him.
He still not ready to divorce me because of social reputation.
What should I do?