I thank everybody for their responses and I have been doing a lot of self reflection from them. I don't want to give up on him but I understand that it may be something I have to do to protect myself.
Last night, I forced a conversation about the lying. It is difficult for me - probably because of the abuse history -to force myself into conversations where I know there could be conflict but you can all tell where it has taken my head. So, I decided to start it regardless of the outcome. I told him how hurt I was that he lied to me and pointed out that he had never fully apologized. At first, he was grumpy, for lack of a better word, over the conversation but then we got down to some nitty gritty and he did apologize and swears there is nothing out there looming for me to find out. I asked him about his commitment to rebuilding trust with me. He said he was willing to work on it. Which, honestly, is more than I expected. I told him that I can deal with him having feelings for somebody else but not with there being such secrecy and slight of hand about it.
So, I'll see what really happens. I'm not wearing blinders on the issues. He was told pretty firmly that if I do find out anything else has been kept from me (told him that omission is indeed lying) I would leave him. I don't want that to be the result but I will do it.