That anger will help you dettach, and you can nurse it, that sounds counter productive.
Anger is a tool. If you use it to help you stay away from your wife, then its not a bad tool. If you use it to verbally bash your wife, then its a weapon and not a good thing.
My MIL was also involved in my sitch, couldn't believe the pi55 poor choices her daughter was making...blah blah blah.
We seem to have alot in common, including finding them in bed together.
I'm telling you this can be done. You're going to survive either way. Stay away from your wife, don't talk to her beyond the basics, bills and Abby, improve yourself, not just physically, not just as a father but as a man and person.
Your realtionship with your wife, what is left of it, is on hold or dead, neither which you know at the moment. And hasty, emotional choices are poor choices made with ramnifications long lasting. Give it some time.
Four years old...what a gift. Keep her safe, protect her from this, do not speak badly about her mother in front of her, build your bond with her, but don't use her for your support in any of this, don't ask her quesions about mom, it's not fair to her.
Experience is a brutal teacher, but you learn. My God, do you learn. - C.S. Lewis
Life is usually all about how you handle Plan B. - Jack3Beans
Listen without defending; Speak without offending - FaithinAK