Okay, so far this thread is not very helpful to you. Cheating is tough. Women do it for a variety of reasons, all of which are selfish, and stem from an unwillingness to communicate or end things without creating a soft landing. But, hell, so do men.
Your question was: "Guys, if you've been through this, how do you quell the anger?"
Here's how. First, you make it you singular goal in life to BE OKAY, NO MATTER WHAT. When our women go crazy and hurt us, it is the biggest mind f*ck of your life, and the your feelings of rage, anger, sadness are all normal. The challenge for you now is to move past it and focus on YOUR OWN HAPPINESS.
You can't control her. The more you try, the less she will respond to you.
So how do you focus on YOUR OWN HAPPINESS?
- Exercise. Hit the gym, join a drop-in basketball, join the Y. Whatever it is, do physical things. These release positive endorphines, help you channel your energy into something good for you, and have the bonus of getting you out of the house.
- Diet. Eat healthy foods. Your body is a reflection of what you put in it. When my wife cheated and left, I smoked, drank, ate like **** for months, lost 25lbs, slept terribly, and was a zombie. It's not worth it. I just felt like sh@t.
- Understand that every word out of her mouth is self-justifying bullsh@t. She has acted like a 1st class c*nt. You didn't do anything to deserve it. It's NOT YOUR FAULT. Don't let what ever lies, justifications, or whatever she spews turn you around on yourself. All marriages have problems. No one is perfect. The marriages that succeed, do so because the partners communicate with each other. They don't step out.
- Understand that "Affairs are a rebellion, and an attempt to find another version of ourselves. As Esther Perel puts it, 'it is not our partners we seek to leave but ourselves'." (Quote from Peter Fox, and excellent resource for info on this - Fidelity summary and internal links
So her reasons have nothing to do with you, and everything to do with her. The other guy wasn't better/hotter/whatever. He was a piece of sh@t, f&cking loser who violated the brotherhood. He should have his balls cut off.
- Focus on things that make you HAPPY. It took me months to ever figure out what made me happy. I hadn't done things for myself in years. I realized, going to a movie alone was fun. Going for a nice lunch and people watching was fun. Getting a massage, felt good. Flirting with women was fun.
Figure out the things you like doing or always wanted to do and start doing them.
The more you get your own life in order, the more she'll notice and realize what an idiot she's been. This may or may not lead to reconciliation, if that's your choice, but you'll come out the other side way better off.
Be strong. Hope this helps.