My narcissistic ex and his mother

I broke up with my ex 4 months ago when I found out he was cheating on me. I didn't hesitate to leave him because he was extremely cruel towards me. He kept me where he wanted me but little by little i felt like i was being discarded, however i didnt know why and what was really going on. He played so many mind games with me. It was the worst experience of my life. The stress got me sick but thank God I had my family's support. His mother reached out to me and I confided in her. I told her I didnt understand what was going on (prior to the breakup and me finding out about the cheating) and she seemed like she was "genuinely confused" also. She told me she would talk to her son and she did but she wouldnt tell me anything he said. Fast forward to when I found the pic of him and the girl he cheated with, I sent it to her and she was able to give me so many details about this girl without even seeing a close up of her face! She didnt want me to confront her son, she kept saying let her handle it but I'm no fool and I wasnt going to let a guy I spent almost 4 years with cheat on me and play me for a fool. Mama ain't raise no mf fool! Anyway, a few days after the breakup, I told his mom I was in so much pain because it really was hurting me badly. I never knew pain like that and my ex lied and had no remorse. He was posting memes regarding having sex with me and not marrying me, as well as how easy he could get over me and I was crushed daily. His mom would tell me she's so sorry and she loves me like her daughter etc. Yet she never acted that way! She now engages with the girl he cheated with, who he's in a full on relationship with. I saw a post on social media where she was sending the girl kisses and loving her pics etc and I feel extremely betrayed. Her words toward me meant nothing. She used to tell me she doesnt know how to ever repay me for the things I'd do for her son and this is how she did me? I understand that's her son but wrong is wrong and how you gonna day you love me like a daughter yet watch your son lie and cheat and hurt me and then accept the same girl he cheated with? Wtf? She doesnt know I know she has a relationship with the girl however and nor did I make it known that I know anything. It's really none of my business anymore because we aren't together but I poured my heart and soul out to this lady and this is how disgusting she moved..just like her son. I'm really hurt but I'm trying to forgive and heal. I've came a long way. My ex still calls me but I've never ever picked up the phone. He was my 1st real love, my first bf, the only guy I ever had sex with. I loved him so much but he fucked me over so badly. Not only did he cheat but he tried to break me down as well. I refuse to be disrespected. I have self respect and self love and no little weak boy is gonna treat me any ole way.