From Derech Emet -
Rabbi Yaakov Kamenetsky taught:
A person by nature does not
think about his own faults.
He must think similarly of his wife
that she is the nicest, smartest,
beautiful, and perfect woman in the world.
And she should have the same
thoughts for her husband.
[I understand this to mean that
since one tends to not find one's own faults
therefore one should treat one's spouse as faultless, too.]
Rabbi Yaakov Kamenetzsky was a leading Orthodox Rabbi,
born in Lithuania in 1891 CE,
died in USA in 1986 CE.
Flatbush Hakhel Event Emphasizes the Importance of a Partnership by Daniel Keren,
The Flatbush Jewish Journal,
2014 January 16, page 58