Cordially,
It's all the human drive toward rationalization. Instead of saying "I goofed. I am a sinner, and I have repented (or need to repent)," he tries to cast it in the best light possible, hoping that God sees it that way too. I don't think God wears those same rose-colored glasses.
In Christian teaching isn't such conduct by its nature the abuse of another person made in the image of God, whether consensual or not?
Either abuse of another of God's children, or abuse of power, or abuse of one of God's gifts to man, namely the gift of sexual expression of love between a man and a woman who are married to each other. Any way you slice it, it appears to be something which separates the bishop from God, not brings him closer. In my book, that's sin. And he needs to repent and make the proper reparations.