NewGirl, I don't think Meredith equates love with sex. I think she uses sex as a comfort...like how some people use alcohol. That's why she kept having all those one-nighters with a bunch of guys after she had to end it with McDreamy.
Think about it. She already has a dying mother and an extremely exhausting job. In this one day she finds out her mom cheated on her father, sees her father after 20 years and things don't go as she had hoped, and the McDreamy wound has been ripped open again. George was just in the right (wrong) place at the right (wrong) time.
I do feel horrible for him and it's going to be sad that his heart is broken, but he chose to go in there knowing that she had no feelings for him.
I think they are both at fault here, but most everyone will blame Meredith.
"My friends have made the story of my life."
-Helen Keller