Thanks all for your advice! It all makes a lot of sense to me, and it is very much appreciated.
My hope is that, as you say, the lies by omission are just a force of habit and nothing to be worried about. But how do I know? It's really just taking a leap of faith.
The thing is that I grew up in a very open and honest environment, and he is the only person who has ever hidden stuff from me intentionally. So, naturally, I want him to be open and honest with me the way things have always been with the rest of the people in my life. My parents used to tell me they didn't care if I told them I had just killed someone, as long as I told them so they could help me...
So, it's very hard for me to deal with lies and omissions. Perhaps the Brotal Honesty method is what we need. I think he would be ok with it, as he understands that I don't trust him 100% and the whole purpose of us giving ourselves a second chance is trying to rebuild the lost trust.
To answer your questions, I haven't read "Codependent No More," and I would be able to not snoop, but I don't know that I would be able to stop worrying (and that's the issue). As for his best friend, yeah... I'm jealous, but she is his best friend only after me.
How does one do "ESH"?