Steve,
Been there and done that. Wife and I been married 25 years (I'm 45) been through our share of ROUGH times from money problems, drinking problems, spending problems and even life threatening bone cancer (my wife has been in remission for 11 years now!). If you love her (obviously) tell her the truth, take your lumps and work through it. It may be rough but you will feel better, there will be no secrets, and once the smoke clears (no pun intended) she will truly appreciate your honesty.
Don't mean to sound all corny, and its just my 2 cents worth. You know whats right and you will do the right thing. We all have opinions, but only you will know how to make it right in your situation. Life is way too short, clear the air and be happy together. :facerub:
Best of luck Bro!