I second Gypsy's recommendation of Not Just Friends. It was invaluable to me and BF in understanding the hows and whys of what had happened to lead up to the affair and dealing with the aftermath.
I will also add a recommendation for After the Affair as an alternate structure to follow post-affair. There are exercises designed to elicit serious thought and sharing if you have decided to stay together.
Focus on yourself, focus on the kids. Take time to do things you enjoy because you need a break from the angst and the raw emotions. Work on detachment. This is an excellent article.
IMO, the OW's SO should be told about the affair. At this point she is the only one in the dark and deserves the truth.
If you love somebody, set them free. http://tinyurl.com/2empx2g