I'm truly and deeply sorry to hear of your wife's response to you. I can't say as I'm surprised, but I know from personal experience how this can cut like a chainsaw to the pit of your chest. They say that adultery is the cruelest thing that one person can do to another -- Dr. Harley says in his talks that it's worse than rape, in that this is a person who supposedly LOVED you, and swore to forsake all others for you. He even had a woman come up to him after one of his talks, who had experienced the pain of both, and who agreed with him. In any case, it's horrific, and I'm sure you're reeling today.
My advice to you would be to take ONE DAY to just absorb the body blow. Nothing's going anywhere today anyway, and you don't want to be reacting out of anger. Pray for guidance, meditate, EAT, and just try to -- as my mom would say -- "be good to yourself." Try to get with some buds or family, even if by phone.
Tomorrow, you need to get into "game mode" or "battle mode." This is where Hooper's been trying to lead you, and it sounds like you're ready for it now. The more you can detach from the emotional side of this, and kind of "hover above it" and see it strategically and tactically, the better off you will be. You will have days when you're unable to do this, and that's okay, but for the most part you need to get to this place in your head.
Document EVERYTHING.
I don't remember your legal sitch, if you're using a base L or what, but I would highly recommend at least an initial consultation with a good family law atty, preferably one who specializes in "men's rights" and paternal custody.
Finally, this:
In addition to the detached "battle mode" I mention above, it will really help you if you can try to think of your wife as an ADDICT. Because she IS one. Serial adulterers usually have a sexual addiction, and affairs themselves -- even one-shot ones -- are highly addictive. This doesn't excuse her choices, but it will help you treat her with detached compassion, and will help you hold on to what's left of your love for her in case she repents and comes around. It does happen, and you'll be glad you treated her well.
That's all for now, other than my digital manly-Sopranos-style hugs.