Have you ever noticed how a little child can run naked through a room full of strangers without embarrassment? He/she is not aware of his/her nakedness, just as Adam and Eve were not embarrassed in their innocence. But, after Adam and Eve sinned, embarrassment, shame, and awkwardness followed, creating barriers between themselves and God.
We often experience these same barriers in marriage. Ideally, husband and wife have no barriers, feeling no shame exposing themselves to each other and God. The moment there is a sin to hide; we put on fig leaves (barriers) because we have areas we do not want our spouse, or God, to know about. Then we hide, just as Adam and Eve hid from God.
In marriage, lack of spiritual, emotional, and intellectual intimacy usually precedes a breakdown of physical intimacy.