P.S. Yes, I agree that he owed you honesty if he said that he was trying to reconcile with you and was not seeing other people or sleeping with them. It seems he has even been working on being more honest. He has, for instance, told you that he is dating and that he has deep dark secrets. He surely has not treated you well as a friend or as a romantic interest.
But this still does not mean the past lies are worth talking about. They are in the past. Unless the two of you choose friendship or a romantic R, there is no R right now in virtue of which the two of you need to work through those lies together.
Until and unless there is a relevant personal R between the two of you, it is pretty much your work to work through your pain on your own, and it whatever future Rs come your way (because the issues won't go away, you will work them out sometime with someone, or you'll be stuck). Same for him. But between the two of you, there is nothing to work out right now because there is not a personal R there right now.
