Couples should know a marriage is both a relationship with God and a relationship with themselves. In fact, Paul advised his readers can remain unmarried in order to concentrate on their relationship with God.
In essence, he was saying if you decide to get married, you must understand that you have to be committed to your relationship with God and your spouse. But some couples believe they only have to water their relationship with God alone and after they have done that it will automatically help to sustain their marriages even if they don't commit anything to the relationship.
Marriage is an Institution Governed by Rules
Marriage is an institution created by God and He has His rules in His Word for sustaining the marriage relationship. God wants couples to be committed to each other in the relationship. He wants them to show each other the needed attention.
God wants couples to ensure the communication lines between them is always on. He wants couples to be committed to each other sexually.