Yes, it's commanded in the word of God. So it's a sin. You almost never hear this taught in church or hear it preached. Nowhere does the Bible tell husbands to "do these 10 things" or "talk to your wife about it" either. To husbands it only says "love your wives". Sometimes, however, "loving your wife" isn't enough. So the Bible commands the Godly (not the feministic) "aged women" to "teach the younger women to love their husbands, to love their children". Why would that work? Perhaps for 3 reasons #1 Aged women are more mature emotionally, spiritually, and mentally: They are wiser. #3 Because it's another woman doing the teaching, instead of some man or husband teaching only because "he wants sex". #3 "Aged women" have already experienced the troubles and the joys of refusing or not refusing.
Also, why does the verse say, "teach them to ...love their children"? Don't most wives put the children first? I'm not sure what all of it entails but consider this: A child is not getting the love and the happy home they so desperately need when Mom and Dad are at constant odds with each other over sex. So if Dad learns to love Mom, and Mom is taught to love Dad enough that there's no conflict over sex, WOW, methinks there would be far fewer divorces and children without a father in the home.