In high school -I want to say this conversation happened either sophomore or junior year- I had a philosophy class, and we were talking about "Wicked Game" by Chris Isaak. More importantly, we were talking about the video.
Here it is, for those who haven't seen it:
http://www.youtube.com/watch?v=-oaHHrNQVrg But anyways, for some reason as I'm sitting here at this Starbucks I keep thinking back to that conversation in class. The professor raised an interesting point about the video- notice how bored the model looks? She's constantly looking away from him. She's in the relationship, physically at least, but emotionally she has checked out.
It raises the same point Racine (French author) did in a play - you don't actually have to cheat in a relationship to be unfaithful. Sometimes, staying there when you've lost the romance, the passion, the emotions in general is even worse. "What a wicked thing to say, that you've never felt this way" indeed. So why do we believe them, even we know -or at least suspect- that they don't even really mean it? We cling on to these phrases because we want to believe they have changed, after all. It's better than the other option - that they never really loved us to begin with, or, the other option, that it's only a matter of time before they leave us too.
Maybe, maybe, that's why we leave them. Because on some level they can't leave us if we left them first.