TexMontana - I know I'm just repeating what others have said, but you are NOT alone. You have everyone here. No need to be embarassed --- no one is wagging a finger at you. I think many people are nodding their heads because they recognize themselves in you.
IMvery,very,veryHO, you should tell your DH before the guilt eats you alive. I found out that my ex-H was keeping financial secrets from me for many years, and I can tell you I would have vastly preferred it if he had told me. I found out by accident and that was the end of it. I left him. Things might have turned out very differently if he had fessed up. So please consider telling him -- you don't know for sure that he will leave, but you stand a much better chance of him staying if you are honest.
