Plot twist after a breakup :)

I’m 23F, and two days ago I found out that my ex was double dating me and another woman. She’s around 33 and he’s 29.
I had my doubts about them, but I never texted her because I felt that would be crossing a boundary. I was just trying to move on, focus on my health, and build something for myself. Then she texted me saying he wasn’t responding to her and she thought something was going on between us.
We spoke, and I was honestly shocked by how much I didn’t know. Apparently they started talking while I was still his girlfriend. He had told her I was just a friend he was trying to help with a job, and apparently told her I was crazy and obsessed with him. Meanwhile, I was giving him space because he told me he was going through a difficult time.
I do agree that I hurt him too. We had our disagreements and misunderstandings, and I’m not going to pretend I was perfect. But I’m still shocked hearing that he saved my name as something else and told her a completely different story about me.
I genuinely feel bad for her because she had no idea about any of this. I can’t blame her when she was also being lied to. The fact that he was continuously apologising to her and begging her to stay honestly made me realise how messed up the whole situation was.
She even met his mom, which I never did because I thought it was too soon. And the weirdest part is, I realised he was following the exact same pattern with both of us.
What genuinely shocks me is how a 29 year old man who is doing well in his career even has the time and energy to maintain two relationships at once 😭
I don’t want his apology, and I’m sure he must be embarrassed to even face me at this point. But I literally told her that if she thinks he deserves another chance, she should give it to him. Just hear his side of the story too. Maybe he has something to say.
I don’t want to be the villain in their relationship or the reason they end things. That’s their relationship and their decision.
I’m not even angry that he cheated. cheating is a choice, and if that choice made him happy, so be it. I’m just genuinely shocked. Funny how people can make you believe they’re scared of losing you while quietly doing everything that could make them lose you.