There are different ways to heal. You should talk to Husband who posts on this board. He lost a leg in a car accident years ago. How do you heal from that?
First of all, no one knows where this is going yet. You don't know how long this affair will last. The majority don't last that long. Have you confronted her and told her how you feel about this? If so, what did she say? Has she said she wants a divorce? Has she filed for a divorce? Just because someone has started an affair doesn't necessarily mean the marriage is over. If that were true, I'd be alone now, and I'm not. My husband and I are happier together now than we were a year ago. Because we went to a program called Retrouvaille and learned how to heal our marriage. Maybe you could do that too.
Look at their website, http://www.helpourmarriage.com and see when they have a weekend near you. See if your wife will go with you. If she will, you will be on the road to healing your marriage and making it better than it was before. Give it a try. Let me know what happens.