Porneia, sexual immorality and romantic love, committed love in marriage
First, about porneia > I think this is listed in Colossians 3:5 as a thing to put to death >
"Therefore put to death your members which are on the earth: fornication, uncleanness, passion, evil desire, and covetousness, which is idolatry." (Colossians 3:5)
Here, "fornication" is porneia. And we are to put it "to death". So, I see this does not only mean to stop the outward and physical immoral actions, but put to death the spiritual depth of it including feelings and emotions and desires that are spiritual but immoral. So, it is stuff that is keeping a person away from relating right with Jesus as our Groom, and with brothers and sisters in Jesus the right way. It means stuff that keeps us from living in God's love. It gets our attention away.
So it is, then, an anti-love thing which needs to be put to death . . . getting rid of what in my heart would have me being immoral. Kill it so I can be alive in God's way of loving, instead. My experience is that interest in immoral activity has different things operating, and which keep me from loving the way I should >
*Interest in the pleasure*, even if I don't act on it, can keep my attention away from personally submitting to God in His peace . . . all the time > as we are "called in one body" to do >
"And let the peace of God rule in your hearts, to which also you were called in one body; and be thankful." (Colossians 3:15)
God's peace is so better than the feelings of pleasure of sexual stuff. To be intimate with nice feelings is not as great as being intimate with God and one another in His peace ruling us. I have found how I can use a woman for pleasure, but my intimacy is not really with her, but with the feelings I like. So . . . it is anti-love . . . using someone, instead of really loving her. And what contributes to this? >
*beauty discrimination* > I can favor a nicer looking woman, instead of loving every woman the way God wants. And immoral attraction can be brought on by how nice a woman acts and looks; so it is not really getting to know her and share deeply. And look what happened when Jacob discriminated against Leah because she was not beautiful like Rachel >
"When the LORD saw that Leah was unloved, He opened her womb; but Rachel was barren" (Genesis 29:31)
Jacob did not want Leah to be his wife; he got tricked into getting her. And he favored Rachel more than Leah, because of what they looked like. And I see how the LORD expected him to love her dearly and completely; and so the LORD enforced this, by not allowing Rachel to have children. And yes I have seen how my way of loving women can be connected with what they look like and how nicely they talk and move.
And a couple of women I have fallen for "the hardest" have turned out to have major personal and character and emotional problems. But they were "extravagant" looking and acting.
But Jesus says >
"if you love those who love you, what reward have you?" (in Matthew 5:46)
So, it is anti-love if I favor someone only because of how I can use her for pleasure . . . physically, or just to look at her, and/or because of how she can charm me. Yes, God "gives us richly all things to enjoy," we have in 1 Timothy 6:17; however, this does not mean for me to discriminate in how I love each person.
Just be careful with the English word 'lust' - the Greek does not have a dedicated word for that; the underlying word usually translated to 'lust' in English just means strong desire, and is also used in a positive sense (use your concordance to look it up).
Paul says how to relate >
"not in passion of lust" > in 1 Thessalonians 4:5.
I think this goes even for in Christian marriage. There can be a difference between lust, versus desiring one another in intimate and tender caring for one another . . . in God's love. God's love is so better than just lust for the pleasure and what the companion looks like and the charming voice.
"Let all that you do be done with love." (1 Corinthians 16:14)
"All things are lawful for me, but I will not be brought under the power of any." > in 1 Corinthians 6:12.
So, even in holy matrimony . . . it seems to me that God wants us to be first about sharing with Him in His love, all the time, and in this intimacy with God we discover how He has us sharing with one another in marriage and our other close relating as brothers and sisters in Jesus.
So, if I am just thinking about using someone, and only using someone to look at . . . this is getting me away from loving her . . . including how instead I need to be blessing and praying for her. And it has me away from staying submissive to God in His peace ruling us in our hearts > Colossians 3:15.