My dear Andy, you are hurting, I see you, I feel your pain... We could be brothers, you and me, similar ages, our respective Ws similar age, our children similar ages, I too have a D(5) and a S(3). My BD was 3 months earlier than yours.
Let her go, she has to go sort her $hit out. There is nothing you can do to help. Do not try to understand her, you can't so don't even try.
DETACH, GAL, 180 and be the best dad in the world for your kids. Don't think about your W, she currently does not give a rat's derrier about you.
It will get better, I promise you, just focus on you and your kids, try to live like she is a neighbor. Be civil, but nothing more. Always have your game face on, let her wonder why you are happy (even if you are not). Do not show feelings around her, if you are overwhelmed, cry in private, tears do wash and clean your soul. Stay busy and keep your mind off her. She is not worth your brain power. I am sure you have a ton of stuff you always wanted to do. Guess what, now you have the time. Go do stuff. Being single in a refreshing change after 15yrs. It will feel weird at first, but I am loving it now. Movies for 1? Why not? Having a beer too many with friends from time to time? Why not? The battle axe is not around to give you a hard time... Liberate your soul, the hurting does no one any good. She will not just snap out of it, she will not come running to your arms tomorrow. Now that you have time, analyze your shortcomings in the M and own your $hit as well. I know you were not the perfect H. Admit it to yourself, own your $hit, forgive yourself and improve yourself. Become the guy only an idiot would leave. If your wife does not recognize the new you, some other lucky woman will.
And to wrap it up, go to joelosteen.com, go under messages and have a look at the video release control. 30 minutes you will not regret. Go now, do, BE!