Sinclair B. Ferguson in his book “Discovering God’s Will” answers what is the ultimate aim of matrimony:
“The ultimate aim of marriage is to reflect God’s image; to reflect the glory of his grace and Being. This means that marriage can never an end in itself. It exists for a greater purpose than its own fulfillment.
When two people are joined in the Lord., something of the glory of God should be seen. The Father’s love for his Son; the Son’s love for his Father; the Spirit’s love for both—these should be at least sensed and tasted in a Christian marriage. If there is grace in it, then there will be a touch of glory in it too. God demonstrated his glory clearly in the sacrifice of his Son. So a marriage demonstrates the glory of God when at its heart there is a spirit of self-sacrificing love.” (Discovering God’s Will by Sinclair B. Ferguson, pp.100, The Banner of Trust)