While I can see why my H did what he did, I will never condone it, or 'ok' it. Its never justifiable. But I think what andyv meant is that he can see how it happened. Heck, at many points even in the LBS's life, this could have happened to us, we just didn't act on it.. I have had chances for EA/PA's throughout our marriage, but it felt wrong, even if I was on the 'outs' with H at the point.
Mark I think you are half and half about your W. You aren't attracted to the person she is, and also you are protecting yourself, pushing yourself away from her to save your sanity. Remember that hot pan? We have touched it so many times, knowing its hot, we don't want to even be near it now, we know it hurts....