How long ago was their affair over. She was your wife, or your girlfriend, when this happened?

Believe it or not, couples do survive infidelity. I've seen it. I've seen relationships get put back together better than they ever were. Your wife's infidelity was a bit extreme. But I can't say for sure there's no way this marriage survives. What prompted her to confess?

Right now you are in major pain. You don't have to make an irrevocable decision right away. Take some breaths. This may be a time to wait before committing to a course of action.