Questioning a general belief on marriage

There is a general belief about marriage that husband and wife should be open to each other; that if they do that and know each other well, they will be a better husband and wife; and their marriage will be great.

I have been thinking about this and asking myself if the contrary is not true. It seems that when husband and wife know each other very well, they tend to take each other for granted; and when spouses take each other for granted, trouble becomes inevitable.

I think more and more that it is better for husband and wife to keep themselves a mystery to each other throughout their marriage. They should keep trying everyday to discover each. Each one should remain unpredictable. Above all, each one should set high standards at home from day one and never depart from them. At the same time, each one of them should have a heart that is full of love and the milk of human kindness.

I am convinced that experts on marriage will have much to say about this but I think we all should have our say. It does not demand one to be an expert to have a say on this. Is it advisable that spouses open themselves like a book to be read by each other and to be fully understood or for each to remain a mystery to the other throughout the marriage?