Marriages Survive Longest On Ignorance

ScienceNews reports that

...evidence lends support to a hypothesis that accuracy in predicting each other’s preferences decreases over the course of a relationship despite greater time and opportunity to learn about each other’s likes and dislikes. 

 Older couples’ knowledge decline partly reflects a tendency by partners to pay increasingly less attention to one another, because they view their relationship as firmly committed or assume that they have little left to learn about each other, the researchers propose.

Here's an alternative hypothesis: Ignoring them keeps you from smothering them  with a pillow while they sleep.