It is not optional to commend the commendable in a marriage.
The evaporating disappearance of affirmation in a marriage is invariably a contributing factor to virtually all divorces. Short of divorce, it also contributes to flatness, coolness, and degrees of alienation.
I can't think of a divorce in which the pair kept up a steady stream of affirming and up-building speech toward each other. Rather, they slid into silence and faultfinding.
But God is at work, even in the most problematic husband or wife. All humans are made in the image of God, and until an individual has breathed his last, God is imaging forth something of himself. It is our privilege to spot such commendable qualities, and call them out with thanks to God.
That's what I mean by commending the commendable. I am not speaking primarily of complimenting one's mate for being good-looking or some other shallow, temporal feature... all of which will assuredly pass. I mean spotting some Christlike characteristic, and thanking God for it - "I thank God, dear husband, that he as made you the kind of man who dependably works hard to provide for his family." Jesus is the most dependable person in existence, and if your husband is dependable, it is because Jesus has given him life, breath, and everything else. "I thank God, dear wife, for your determination in protecting our children." Jesus is the most determined person in existence, setting his face to go to Jerusalem to fulfill the Father's will at the cost of his own life, and if your wife is determined to serve her children, it is because God is working in her both to will and to do his good pleasure.
Husbands and wives who commend the commendable in each other honor God, refresh and encourage each other, gain a hearing from each other, model good things for their children and others who are watching, elevate the atmosphere in the home, and set up the possibility that the refreshment they have sown will come back to them at the right time.
God created and has good purposes for sex in the context of marriage, and we don't always view it rightly.
People are susceptible to believing all sorts of misconceptions about the purposes and practices of marriage.
Genesis 1–3 defines marriage and shows us that marriage began in the Garden of Eden, in a perfect world.