This ideal has already been destroyed. In my opinion, if he's lied to you so many times in the past, he's bound to lie again in the future. You've already proved to him, by staying with him, that his lying to you has no negative reinforcements. I would suggest taking a break for yourself and perhaps enjoying a relationship within which there are no doubts. You will not be able to be completely open and free in love, if you are not able to trust the person with whom you are in love.
Relationships are hard work.
A relationship with a liar is a thousand times harder.