Am I in the wrong here?

So I’ve been with my partner for 7 years and we have 5 kids together. Not too long ago, I found out that he was cheating on me and that it had been going on for 8 months. He wasn’t even just cheating, he was living a whole double life. She was practically his girlfriend. It was very stressful, the girl was threatening me after I started calling her and texting her and then she brought my kids into the mix. She started calling the authorities on me making false reports on all of us. I came to her job twice because I was really mad and was looking for her, when I found her at her job we were screaming at each other and nearly came to blows. I left. It got to the point that detectives got involved and told us all to leave each other alone. We did that.

This morning, I woke up and decided to look at his phone. It was her. She was texting him trying to get back together. Then she called his phone. To ensure it was her as I could’ve been mistaken on who it was, I called private and it was her voice. I hung up but I called her back private 4 more times and she didn’t answer. I’m so angry. He told me he was no longer in communication with her, and even if true, which he hasn’t been responding. She’s still texting him. I want to talk to her and if I can’t get through I’m feeling like I wanna go back to her job. Not to mention she’s claiming to be pregnant. While we were arguing a few weeks ago she sent me a video of a positive pregnancy test.

I’m so fucking mad and I get it, we’re 29 my man and I and she’s only 20, but she knows what she’s doing and needs to fucking stop.

EDIT TO ADD- Just some detail, she is 1000% aware that he has a family at home and refuses to stop contacting him. She will send 14 texts, he responds to none. Idk if he’s calling her or not behind my back but I just wanna make everyone aware that she straight up told me once that just bc he’s sleeping with me and has a family doesn’t mean she’s going to break it off with him. Those were her words.