Yes. She does. We've discussed this at length - some of her friends do the same to their game-playing boyfriends. Apparently, there are 3 reasons why girls do it:
Singleplayer: They want the story, but can't be arsed to actually play the game themselves (they don't have the talent, understanding of game devices, motivation, or interest in that game type) - this is the case with my girl and watching me play Oblivion. She's been there for most of my 90+ hours of playing.
Multiplayer: This is similar to watching their man compete in a sporting event. It's always fun to watch him prove that he's better than someone else.
Or, they just want to watch the pretty flashing colors.