To the spouse who had the affair, it's time for what I call a multilevel apology.
Anyone can say "I'm sorry," and it's important those words are spoken. Then follow up with an acknowledgment of the pain you caused and a commitment to never let it happen again.
In order to rebuild trust, you must be willing to live under a microscope for an indeterminate time. It will stink and be very uncomfortable. But it's a necessary part of rebuilding trust.
One of the first rules of living under a microscope is to avoid doing anything that will increase the magnification.
You must break all ties to the person with whom you had an affair. Sometimes this is easy, other times it is not.
If you work in the same office or go to the same church, make sure you are NEVER alone together. If you find you're tempted to continue the relationship, I have a three-word suggestion:
Run like hell!
I worked with a couple once where the man ended up alone in an office with the woman with whom he had had an affair. When it became crystal clear she was trying to pull him back in, he literally ran out of the room. He may have looked silly and even been embarrassed, but he saved both his integrity and his marriage.
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