Leviticus 18

There is to be no uncovering nakedness. Of anyone considered a relative their nakedness is not for an Israelite to know. I think this means looking, or trying to get to a place of nakedness between two people, not the actual act of having sex. I only say this because in verse 20 it states differently 'sexual intercourse' as not to be done with the neighbor's wife. The rest of the chapter is about not having sex with those like you in gender, or animals. Those are called abominations and perversions.
I wonder though if the loose interpretation of looking at a neighbors wife but not having sex with her is how David gave birth to sin, and sin to death, with Bathsheba? Isn't it so true that what we most often do is not deliberately break a law of the LORD but conform it to our minds. Which is the exact opposite direction God apparently wants our minds conformed, "therefore be transformed by the renewing of your minds...". A line Paul utters in his letter to the Romans, a book that is wrought with Christ's idea regarding the heart. Jesus states almost redundantly the call of God is to the heart, for change and renewal.
We will see later in the new testament that Jesus states that even if a man look upon a woman with lust for her in his heart, he commits adultery. We, as men, should regularly think on this truth. In light of this chapter about the lewdness of uncovering the nakedness of a relative, let's revisit what our hearts, through our eyes, are delighting in. Maybe it's just me, but lust seems to have a new face with the same motives, even after marriage.

"You are to keep my charge, that you do not practice any of the abominable customs which have been practiced
before you, so as not to defile yourselves with them; I am the LORD your God."