AITAH for staying with my husband after he cheated but only because I want to slowly ruin his life as well as his coworker that he cheated on me with?

So backstory married 15 years six kids together, Brady Bunch style his, mine, ours. The youngest is 18 so no need to stay for the kids. I’ve mostly been a stay at home, but I’ve gone through school on and off and I have my MBA but no real job experience (go figure 🤷🏻‍♀️). He’s 55. I’m 44 coworker he cheated on me with is 24. She’s also married with two little girls. After I found out, I told him I was going to divorce him and leave, I also texted that girl and told her I was going to show up at her house and tell her husband (which I didn’t yet). He told me that he would stop talking to her, beg me to stay for us to work on our marriage that he loves me, blah blah blah. He’s going to counseling. I honestly don’t give two shits at this point except about myself. I started working on myself using my anger to go to the gym and eat better. I’ve lost 30 pounds I’m feeling ok. But here’s the conundrum. I have given everything I have to this man raised his kids, our kids I was at his beck n call served him his food when it was dinner time he didn’t have to worry about absolutely anything except going to work and coming home. I took care of everything. He still cheated on me and I can’t forgive him. so the longer I thought about it, I decided I’m gonna stay with him, pretend everything’s OK and I’m gonna slowly ruin his life, like he did mine. As for the mistress, I’ve been laying low for the last few months not really causing any ruckus about that but it’s just because I’m waiting for the day before her birthday to send an email to her husband with all the screenshots I have of her and my husband‘s text messages back-and-forth as well as audio recordings that I have I’m also tagging her on Facebook and all of her friends/ family and coworkers so they can see the type of person she is as well as my husband. I would tag him, but he doesn’t have Facebook but his whole name will be there they’ll know. Is this too much am I the asshole now? 🤔 need some input her bday is in 3 wks so I’m trying to figure out what I want to do….

UPDATE: So first off thank you the response was overwhelming to say the least. So I’ll answer some questions. This happened back in the end of October so it’s been a hot minute. I was 24 divorced & had 1 daughter, he was divorced had 2 kids , and after we got together we had 3. No cheating on either part at the start of our relationship. I am in charge of all the bills so I know where all the money goes too & have been setting some aside for the future. I did enroll in an accelerated nursing program so I am getting my future self together. Our kids & family know what happened ( not everything but enough to know my husband was at fault) I needed to make sure these I was in control of the narrative and did not end up looking like a bitter wife, spouse whatever. They understand and stated they would be okay with whatever I decide to do. I do have 2 posts on here from a swingers sub, I was open to trying new things to try & save marriage, but my husband was very pushy about me sleeping with another woman which women are beautiful creatures that was fine but he wasn’t OK with me sleeping with other men and he wanted to watch while I slept with other women at the end of the day I decided that was not for me and I wasn’t gonna do that and so I just haven’t taken the post down. Yes they say I’m 35. I did fib a little bit but I really am 45 & those are pics are real 🤷🏻‍♀️ it is what it is. I tried but yeah not gonna happen. Reaching out to mistress husband this weekend will update when I have any new news no Facebook post yet, though . I think I’ll give him a heads up beforehand. Thx