Husbands and wives in Christ can be pleased by God’s design for sexuality and be unashamed in nakedness, but our corrupted nature reminds us that we no longer live in the Garden.

At the time when Adam and Eve were completely naked and without embarrassment (Gn. 2:25), the world was perfect. Man and wife had no lustful thoughts. There was no such word as “sexy;” instead, the word was “holy.” God covered animals with fur, feathers, scales, and so on. But God covered man and woman with His glory. And why wouldn’t He? He made male and female in His image. God Himself is covered in glory (Ps. 104:1-2; Isa. 61:3-10).

Sin changed everything for Adam and Eve—and all of us. Their eyes were opened and they knew that they were naked (Gn. 3:7). Nakedness was no longer “good.” Their sin left them exposed and vulnerable. New emotions of embarrassment and shame caused them to cover themselves with fig leaves. They sewed for themselves a loincloth and bikini of fig leaves but, still very embarrassed, ran to hide. God could have left Adam and Eve in their naked and hopelessly sinful state but He had loving compassion. Before He sent Adam and Eve out of the Garden, God did something for them that only a merciful God can do. He knew that a bikini or loincloth of fig leaves would not be enough covering in the sinful world so He covered them with garments of skins.

Martin Luther writes,

Here Adam and Eve are dressed in garments by the Lord God Himself. Whenever they looked at their garments, these were to serve as a reminder to them to give thought to their wretched fall from supreme happiness into the utmost misfortune and trouble. Thus they were to be constantly afraid of sinning, to repent continually, and to sigh for the forgiveness of sins through the promise Seed. This is also why He clothed them, not in foliage or in cotton but in the skins of slain animals, for a sign that they are mortal and that they are living in certain death. (Commentary on Genesis 3:21, The Lutheran Study Bible)

No man or woman on this earth, not even husbands and wives, would ever look at one another in the way that Adam and Eve did before sin. Original sin put corruption into our human nature and radically impaired our desires. Now what God created to be “good” nearly always brings forth evil desires. Not even the loving and procreative act of sex made for the faithfulness of marriage between one man and one woman would, on this earth, be quite the same.

Clothing was unnecessary in the Garden.  But we are not in the Garden anymore.  Clothing can remind the baptized Christian, single or married, that we are washed and robed in Christ who calls us to a life more holy than sexy.

From Chapter 14, Question 86
The Failure of Sex Education in the Church: Mistaken Identity, Compromised Purity
by Linda Bartlett, Copyright 2014 Titus 2 for Life
Our Identity Matters