Am I wrong ?

So me and my ex ended things a while ago but just recently started to stop acting like we were together. She started liking this guy but would always down play the relationship between them. As I friend I was happy for but as a former lover I was heart broken. She still claimed to love me and be in love with me but we couldn't be together for religious reason. I couldn't understand how she could move on and start liking someone so fast. Our friendship blossomed but as she was talking to him me and her started having sex. It was unplanned. This happened for a few months. I was under the impression that her and the guy weren't really dating and they hardly saw each other stuff like that. I know it's wrong to sleep with someone whose talking to someone else but we couldn't help it. And most of the time I was the one who stared it. She was always hesitant at first but then she gave in. We both gave into our temptation. After months of this I had the weird feeling that her and this guy were having sex. I mean I asked her prior but she denied it every time. So I believed her. Come to find out that her and the guy are more serious then I thought and that she and him have been having sex for months. So she was having sex with me and also having sex with this guy and lying to me about it. I feel so heartbroken but I'm also angry. I was so angry that I messaged the guy and told him that she was sleeping with both of us. He had no idea that she was doing that. Now she's mad at me for telling him because she's scared he's going to leave her. She said I shouldnt have helped aid her into having sex with me. She says she doesn't blame me but I play a big part in this whole situation. Which I do. I shouldn't have aided her into doing something with me but she also said I was wicked and vengeful for telling the guy. Which I don't think I am wrong for. She wasn't going to tell him and she lied to him about sleeping with me previously because she was scared to loose him. Now she blocked me because she says she can't talk to me and build a a new relationship with him at the same time . And she makes it seem like I'm the worst person ever because I told him that she was having sex with both of us. When she was the one who has been lying for months, putting my health and heart and the guys health and heart In jeopardy. She claimed that she didn't tell me because she didn't want to hurt my feelings. But my question is am I wrong?I feel horrible and I'm heartbroken.