"And those who say: Our Lord! Grant us from our wives and our descendents coolness of the eyes and make us an example for the people of piety."
[Noble Quran 25:74]
What is alluded here is that the righteous servants of God do not care about correcting themselves only, but also take care of the virtuous actions of their children and spouse, and keep trying for their improvement, and it is a part of their efforts that they pray Allah to make them take the right path.
Marriage is one of the most important social relationships in society. If it goes sour, there is little hope for the overall society - especially the next generation.
The affection which Allah has created in the hearts of the two spouses is one of His great signs for the people of understanding. The relationship between husband and wife should be one of affection, compassion and mutual understanding.
If husband and wife do not find this in their marriage, then they need to look to their Islam and the completeness of their uboodiya (slavery and complete worship) to Allah Most High. By each of them focusing on the completeness of their Islam and carefully maintaining their obligations toward the other - instead of focusing on the faults of the other and attempting to use Islam as a stick with which to beat them down - the affection, compassion and great calm or peace of home life will insha'Allah be found.
The righteous slaves of Allaah also ask that, in their sayings and their actions, they should be made an example for those dutiful to Allaah, that their actions should be followed, that the people have confidence in their sayings, and that the people of good follow on behind then so that they, themselves are upon the guidance and give guidance to others.