I have never heard anyone speak of this that marriage is like a mirror, but it is when you look at it from the context of the flesh and the Spirit, it makes sense. Let me show you what I learned regarding this.
God created man and woman in the Spirit first as it is written in Genesis 1:27 So God created man in His own image; in the image of God He created him; male and female He created them. Then after this He created man from the dust of the earth. Genesis 2:7 And the Lord God formed man of the dust of the ground, and breathed into his nostrils the breath of life; and man became a living being. This is important to know this as what God created from the flesh is of the Spirit.
Now after God took the rib from the man and created woman, He said this, Genesis 2:24 Therefore a man shall leave his father and mother and be joined to his wife, and they shall become one flesh. So the two now become one in the flesh so they can fill the earth with the Image of God. God commanded this back in Genesis 1:28 before God made made from the dust.
Now lets take a look at this as a mirror. When Jesus came on the earth, He came to pay the price for sin for the entire world. But there was another objective for Jesus to go to the cross. When Jesus got beaten beyond recognition, you know that He couldn’t die, right? Jesus knew no sin and sin is death so He couldn’t die until sin was put on Him. On the cross, it was dark from the 6th hour to the 9th hour. After this Jesus says something that you never have heard Him say before this point. That is “My God, My God, why have You forsaken Me?” Matthew 27:46. At this point Jesus was separated from His Father. This is what sin does to you.
Now that Jesus has been separated from His Father, He can now be joined to His bride in the Spirit. His bride must prepare herself. For this she must be born of water and Spirit as this marriage is of the Spirit. When you are born again, you have are buried with Christ in baptism so you can be one with him in the Spirit. You have been crucified with Christ; it is no longer I who live, but Christ lives in me; and the life which I now live in the flesh I live by faith in the Son of God, who loved me and gave Himself for me Galatians 2:20 Jesus had already prepared himself for this marriage of the Spirit. Paul explained that when you are joined to the lord, you are one Spirit with Him. This is the marriage of the Spirit.
Revelation 19:7 Let us be glad and rejoice and give Him glory, for the marriage of the Lamb has come, and His wife has made herself ready.” 8 And to her it was granted to be arrayed in fine linen, clean and bright, for the fine linen is the righteous acts of the saints.
He who has an ear, let him hear what the Spirit says to the churches spoken to all the 7 churches in the Book of Revelation