We never meet the expectations of our mate.  Sometimes they are reasonable.  Sometimes they are not.  Each of us are very flawed.  Another way to say the same thing is each person sins.  Not one would say they are perfect (or never makes a mistake).  That is why forgiveness at the end of the day is so important–to wipe our slate clean.  We never completely meet the expectations of our mate.  It is impossible.  We are all imperfect.