The Designer, the Lord Jesus, gave the reason for divorce in Matthew 19, "hardness of heart," and that's all that can be said about it. That's disobedience to the designer.
One large problem with professing Christian families is that they delay any proper instruction on these subjects until one of the children announces some seriousness about an involvement with someone else.
Good instruction about marriage begins from early childhood. Even children can be taught the picture of Christ and His Church which is permanent and the proper care between husbnad and wife described in that light (Ephesians ch. 5; etc.)
Then making proper, guarded friendships from early years. Children who are not taught how to make the right kind of friends in general most often don't know what they are looking for in a spouse.
And so much more. As a pastor, in 39 years thus far in the ministry I have performed only five weddings, and am very happy about the low number. I only perform weddings for people who have been under my ministry for a long period of time, usually from childhood, and we know the character and church attendance consistency of the one they will marry as well.
I wrote a paper in 1982 called "Standards for the Marriage Altar" that is read by all people associated with our ministry. I make no exceptions to those standards, and I don't allow the couple to use me as an option on a drop-down menu just to suit them so that they can get married. It is NOT required of ministers that they perfor wedding ceremonies---it is not a qualification for the ministry in the New Testament. I'm not afraid to look a couple in the eye and say, "I don't have to do this, so I will give you the standards, not the other way around."
“It is NOT required of ministers that they perfor wedding ceremonies-—it is not a qualification for the ministry in the New Testament.”
I recall reading about the Pilgrims and John Bradford. It came time for a couple to be married, and they pondered how to perform the ceremony under their new form of government. He wrote something like “Seeing no recommendation from the Scriptures, a civil ceremony was performed.”
I was surprised by that.