I'm betting if I asked you if you've ever been lied to, your answer would be yes. I suppose we all have and I think the degree of damage it causes is equal to the depth of caring we have for that person.
I remember soooooo many times in my life when I felt the obsessive need to gather evidence so I could prove someone betrayed me; to show them that I was not that gullible; to try and express to them that without trust, there can be no true intimacy nor real depth to our relationship. And although there was an enormous amount of my own healing twisted up in there, the walk was utterly exhausting!
It took a very long time to reach a place of peace regarding all this. It used to break my heart into a million pieces and do such a number on me that I harbored doubt, pessimism and hesitation in my belief that an open and honest relationship was possible. It filled me with uncertainty and caused me to pull back my love and shield my heart, so as never to be burned again.
But now I know better. I know that when someone attempts to deceive me, it really has nothing to do with me, especially when the same person has done it again and again and again. It still causes a deep sadness within my heart, but now it's more for them - that they feel the need to lie when it's unnecessary; that they waste so much of their precious time making up stories to cover their tracks; that they don't honor themselves, nor trust the world and people around them enough to courageously live the truth of who they really are in every moment of their lives.
The thing to always remember is that although a lie may take care of the present, it has absolutely no future.