Adultery is the head of a family of sins which are an outrage and a betrayal of a special bond or relationship. You could say what is behind adultery is pride and greed.
You cannot possibly have wisdom if you're playing with fire. You may tell yourself that you are not actually going the whole way, but you relish something that you know is unspiritual or sinful or wrong or inappropriate, and you think you can go so far and not be drawn in. No, you can't have wisdom because you are doing something, says the scripture, which is so foolish, so stupid. And wisdom won't lean on a foundation of stupidity. The Christian who's being stupid and playing with fire can't possibly hope for the Lord to add to him wisdom