When Adam had lived one hundred and thirty years, he became the father of a son in his own likeness, according to his image, and named him Seth. Then the days of Adam after he became the father of Seth were eight hundred years, and he had other sons and daughters. So all the days that Adam lived were nine hundred and thirty years, and he died (Genesis 5:3–5).
If there is any question that God's intent was a one man, one woman relationship until death do you part, you do not need to look past Genesis 5. God created male and female. God brought them into a union (a marriage) in order to reflect the reality of Christ and the Church (Ephesians 5:32).
Perhaps in the days of Adam, this scene occurred.
"Surprise!" "Why Eve! All these hundreds of relations gathered together. You did remember? Yes?" Eve replied, "Of course, Adam. You know the preciousness of the love that our Lord has gifted to us." Adam answered with moistened eye. "The mercy of the Lord endures forever. You are a gift."
Adam joined hands with Eve after a tender embrace. Eve kissed his moist face. "Come. People are waiting." They entered into a large room that was full of sons and daughters, children and grandchildren. Shouts of joy and laughter echoed around the room. There were tables of feasting set before them. All of this provided by the Lord.
What was the occasion of such love and joy? Adam and Eve looked upon faces of joy. Their gaze moved together upward on the wall. A high and lifted up banner was apparent for everyone to see. Adam and Eve gazed upon it in joy and thanksgiving. The words echo in both of their hearts for His mercies.
"Happy Anniversary! 900 Years of Loving Faithfulness!"
Behold, in a day of broken covenants and marriages that cannot last five years, does God still design marriages to abide until death do you part? The answer, YES.
At your next anniversary, remember that your life together is still very much a babe compared to "in the beginning". A golden fifty year anniversary is a gift from the Lord. However, it is nothing compared to a marriage of 900 years!