Whatsapp chat and no sharing

I shared number on WhatsApp group of a call girl I have 6-7 contact saved in my contact list as call girls and they are professional escort. After 2 days I start receiving msg on my facebook messenger and WhatsApp all with absuing language and all the guy also send me 2 sceen shot (attaching same) I am out at sea my network was extremely very poor due to VSAT blockage area. After 2 days when somehow I manage to download screen shot I found the number which is claiming is saved in my phone by call girl name. I keep on asking him but he didn't tell whose number is this and told me will lode FIR against me in police station, crime brach and women cell and was using all absuing for my parents and family. To which I told if u have anything with me keep my family away, he was continues using aggressive and abusing language for my mother , father and sister. Later I check from my sources the number he shared with me is of his wife and when I checked same number is saved as call girl name in my contact list. His wife was my girlfriend ex girlfriend we were in relationship for 8 years. I have deleted her number long time back and sorry I am too bad in remembering phone number. Honestly I have no clue how her number is saved as call girl in my contact list. I used to save her number by diff diff names when we were in relationship might he saved from that time but I am not sure about it. Now her husband want to file case against me for sharing her number in WhatsApp group. I would like to clear following questions with you. 1) If he want to file FIR why did he msg me and why did he use abusive language for my parents. 2) screen shot doesn't prove I have shared that number see attached screenshot. I can defend myself he want to defame my image since he come to know his wife was in relationship with me. 3) Since we were in relationship for 8 yrs she we had sex more than 1000+ times , I can prove that and I have transferred money into her account for something can I prove with that she is a slut if they file case against me . 4) can I file case him against defaming my image and false allegations against me and using abusing language against my parent's. 5) if they file case against me how can I defend myself.