Should I feel embarrassed or proud

Harp
So my ex and I broke up in August. In December we officially ended it. But during August through the December we were talking on and off. I met another man and really liked him and would talk to him a little but I still had feelings for my ex. Anyways, in December, while I was spending time with my ex he asked for my phone. I refused and he called me a liar for refusing to tell him that I am talking to another man. FYI I'm 26 and my ex is 39 and we work together. He said so much shit to me. Recently I found out that he is already screwing another girl from work. And he was at a bar with her for our holiday shutdown for work ( and would always tell me that he doesn't drink) BULLSHIT!! 
And the girl was so wasted I heard that she took her pants off. I've never been so angry in my life like I am now. He lied to me as well but even went a step further and already was having sex with her, someone who has no shame. Smh. Should I feel proud or embarrassed? Of course I'm never going back to him. He's the most disgusting, selfish human being!!