So, what is the point of being completely open and honest with your wife, and walking in brokenness before God in your marriage? Why can’t my sin be just between God and me? Won’t my marriage be much more peaceful if I just deal quietly with God over my sin, rather than upsetting my wife with it?
The answers begins with the purpose of marriage:
“Therefore a man shall leave his father and mother and hold fast to his wife, and the two shall become one flesh.” This mystery is profound, and I am saying that it refers to Christ and the church. Ephesians 5:31-32
Thus, the goal of my marriage is to present to the world a picture of Jesus Christ and his relationship to the church. One aspect of that relationship is that he died for the church, setting us free from bondage to sin and taking the punishment for our sin. He also died and rose again to restore our relationship with God, which, for Adam, was daily fellowship, just as Jesus Christ has fellowship with his father:
But if we walk in the light, as he is in the light, we have fellowship with one another, and the blood of Jesus his Son cleanses us from all sin. 1John 1:7
If I wish to have fellowship, I must walk in the light. Not just fellowship with God, but fellowship with my wife.
In the broader context of 1 John:
This is the message we have heard from him and proclaim to you, that God is light, and in him is no darkness at all. If we say we have fellowship with him while we walk in darkness, we lie and do not practice the truth. But if we walk in the light, as he is in the light, we have fellowship with one another, and the blood of Jesus his Son cleanses us from all sin. If we say we have no sin, we deceive ourselves, and the truth is not in us. If we confess our sins, he is faithful and just to forgive us our sins and to cleanse us from all unrighteousness. If we say we have not sinned, we make him a liar, and his word is not in us. 1John 1:5-10
In short, if I am hiding my sin from my wife, claiming that I am not ____________ (fill in the blank…”looking at pornography” “committing adultery” “cheating on the finances”), then I am walking in darkness. If I am walking in darkness, I cannot have fellowship with my wife. If I am not in fellowship with my wife, we are not a picture of Christ and the church. If we are not a picture of Christ and the church…we have missed the whole point of marriage.