I am dealing with this in real time - at an early stage. I found a note that my wife had drafted to go to a guy with whom she is infatuated, but with whom she has not openly and directly shared her feelings. She saw me find the handwritten note, which she left openly on our computer keyboard. She was toying with sending an email. That was 4 months ago. We are wrestling with the temptation that she has had to deal with, and the sense of assault, insecurity and betrayal that we both are feeling. I think that we are rare, in that I discovered this at a very preliminary point in the process. Left unchecked and unknown, even she admits that she does not know where it would have gone (and, frankly, I am not sure if the whole ordeal is over). What I can say is that this is a spiritual attack on her and on us. Satan has taken the opportunity to attack both of us at our weakest points.
But let's not kid ourselves - this issue is ancient and part of the result of the primordial fall. The roots of this sin are not really in adultery or even unfaithfulness - they are in covetousness. Wanting something that God has not provided for us. The 10th commandment, leading us up a ladder of sin. And who is so spiritual that they are beyond temptation in this area? My wife was taking stands for the Lord and growing stronger in her faith and commitment when this struck. And she shared her struggle with me, as hard as it is for me to accept. All I can say is that we are not as strong as we think we are. We have been married 20 years, love the Lord, love each other, have wonderful young children who love Jesus, faithfully attend church and are involved. I have served on church leadership boards and preached from pulpits. I have been involved in church discipline for others who have fallen through adultery. But I know that I have failed my wife in many ways over the years, have put others and work before her too often. Have I loved her as Christ loved the Church, given myself up for her to make her spotless and holy, without stain or blemish, to present her before God? No. And I know that she was not looking for this temptation, nor does she want to leave and fall into sexual sin with this man (she has not). Still, we are visited with this attack. The struggle is very real.
We need to recognize that this temptation is as it says in I Coritinthians. It is a temptation that is common to all, and one for which God has given a way out. Stay tuned. God willing, HE will prevail and be glorified in victory over this sin and in greater humility and devotion of his servants - husband and wife.