Person who coined the phrase "love means never having to say you're sorry":

Erich Segal
On December 17, 1970, "Love Story" was released, a film written by a Yale Professor named Erich Segal which told the story of two Harvard students from different backgrounds who fall in love. In addition to being one of the highest-grossing films of the early 1970s, the movie also inaugurated the phrase "love means never having to say you're sorry."
Source: New York Times, 1/20/2010

 
   
  Number of the 67 million opposite-sex couples who lived together in the U.S. in 2008 who weren't married:

6.8 million
According to the U.S. Census Bureau.
Source: USA Today, 2/26/2008

 
   
  Number of opposite couples in the U.S. who lived together in 2008:

67 million
According to figures from the U.S. Census Bureau.
Source: USA Today, 2/26/2009

 
   
  Sales of jewelry for Valentine's Day in the U.S. in 2008:

$1.56 billion

Source: Wall Street Journal, 12/13/2009