"If I encounter someone I don't necessarily like but I still acknowledge him/her out of courtesy, so if I'm this nice and polite to other people, doesn't my wife deserve the same? Times ten?" These days on the rare occasions that I do see her I do have a different greeting (happy one) than when we lived together (no greeting). Never take things for granted, even a simple smiley face.
This chapter also talked about being "...gracious enough to address even your enemies with kindness." I think about the man she had (or still has) an affair with and I just can't see how I can greet him with a smile and a hug. In fact, I want to hit him I really do because I am angry towards him. I know it is not what God wants. I still see them exchanging FB messages and that makes me angry :( , by now she has blocked me and all our mutual friends from her wall, but there are still some parts visible.
James, this may be a huge roadblock for you. You need to pray about it.
If you and your wife get back together. Will you have forgiven her? What about him? I do not know the whole story and everything goes on, but if you forgive her, you are going to have to forgive him. And only the Love of Christ within you will give you that ability. That does not mean you need to great him. But you need to allow Christ to comfort your heart.
Deep down I know that's God's way - forgiveness, even my enemies. It is so hard, especially from all the details I found out. One thing I'll do regarding is - I'll pray.
Forgiveness is a tough thing especially for Men. God wired us with a pride that is a battle of its own. But there is one way to overcome that.... Trust in Christ.