My ex is seeing my friend?

I was with my ex for 6 years, was engaged and I broke it off with him two months ago to be with someone else. Before I get judged, he had no ambition to do anything with his life, I basically paid for everything and he didn't support my education. He took it really hard. Begging me to marry him and have a baby. I felt that I was over him completely until I ran into him and one of my old friends "together". He used to talk so negative of my friend, so I was shocked. I got upset because at first my thoughts were "he's using her", I ended up yelling at him. She later on started texting me saying that she felt awkard, that he keeps trying to sleep with her, and that she didn't want to hang out with him. When I asked her to respect me and not date him, she kept switching the subject. She was saying that he still loves me, talks to her about me, and that he called out that night because of me. But then tells me "I didn't think you two were that serious" which was her reason as to why she's talking to him. When I said he was using her, she got all defensive. Why get defensive if she doesn't like him? I found out that she's still close to her ex, which seems like that isn't over with. My ex and her work together and he's actually her boss, and I mentioned that. I threatened to say something. They can't have an actual relationship because he's her boss, so what's the point? So he calls me telling to me telling me to leave it alone. I would bring her up and he would say that he didn't care what she was doing, that the conversation was about him and I, and how I'm acting. He said that I hurt him and that we both moved on. The conversation ended badly and now he isn't answering me. I just don't get it. Why do I care? Why am I hurting when I wanted to be out of the relationship? Why would my friend be a snake? Is she into him? Is he using her? He takes her out in public but he could lose his job, so why? Does he still love me?
My ex is seeing my friend?
Add Opinion