Dealing with a Liar

I have found that I have trouble dealing with people who lie.  S says this is because my brain doesn't work that way.  I always try to tell the truth, so I operate as if everyone tells the truth.  Today, I read an article titled "Understanding a Liar"

For me the most interesting part is this:

"In relationships you are responsible for your half of the emotions.

"Taking care of your half means noticing where you are lying. If you are upset with someone for lying it is because you believe they should be telling the truth. Your expectation is that they should drop all their years of social conditioning overnight.

"You believe they should adopt a new behavior and become a person you expect them to be. You believe they should be the image you hold in your mind about them. They are not the image in your mind that you want them to be. When you want another person to live according to your expectations you are lying to yourself about who they really are."
http://www.pathwaytohappiness.com/happiness/2007/07/30/understanding-a-liar/ 

I can see how this is true, but it is difficult to apply.  I can see how my expectations color many situations, but I had never applied it to someone else's lying.  If I expect them to behave differently than they actually do, then clearly I am causing my own distress.  Does this mean that I simply accept that they are going to lie and be okay with that?  Does it mean that I just prepare for them to lie because they are going to lie anyway?  Maybe I'm not okay with it, just accepting and therefore prepared?  What do you think?

So, if I am lying to myself about who this person really is and creating my own distress in many ways, how do I move passed those expectations?