It's been four years since I caught my wife in an affair, so I am more likely to have your wife's perspective on this one. However, I don't think surviving an affair automatically makes any of us experts.
I can point you toward a few resources that helped us, though. My favorite (and the likely reason we survived the initial impact) is a weekend-long course offered by Joe Beam for marriages in crisis. It will revolutionize your marriage. Check him out at
www.joebeam.com.
After that, re-group and see where that leaves you guys. Additional therapy will likely be needed, but maybe seek advise from Joe on therapists that are properly trained to help in matters of affair recovery.
Also check out a number of very good books: "Your LovePath by Joe Beam; "Becoming One" by Joe Beam; and "His Needs / Her Needs" and "LoveBusters" by Willard Harley.
Just your energy placed in the direction of seeking as much help as you can will have an impact all by itself.
Hope this helps you get started.