Lie to me, tell me everything is alright

I've started to realize that maintaining a friendship with someone you don't trust, is really hard. I feel like I am on the constant lookout for a sniper. Or like I'm a detective, on the case of "The Hidden Lie". The time you spend with that person no longer becomes enjoyable, because all you can think of is what it will feel like when they hurt you again. You become paranoid, and you overreact and think that they are lying when it is just miscommunication, or a lack of better judgement. And then you become the crazy one. And if I choose to forget it, and start trusting them again, I know the moment I feel comfortable trusting them again, they are going to pull a fast one on me.
It is now apparent to me that friends who lie aren't friends at all. But it's hard to let go. Because I know that there was something good in the beginning. If there wasn't we would have never become friends. And I have to wonder if they are lying because they care about me, or if they are doing it out of selfishness. In the situation I am in, it is out of selfishness.
There isn't a lot left to hold onto. Especially because I know that when they apologize they aren't really sorry. And I know that it will only be a short while until I lose all self respect for staying in the relationship.