How Much Should You Confess About Your Past?

The issue never really goes away:  How much should you confess to your husband or wife about your past life?  Or even your present life?  Following a series dealing with the consequences of infidelity, we were bombarded with several variations of the same question.  One person wrote, "I have confessed my sins to the Lord and truly experienced the joy of His forgiveness as I claimed His blessings, but I always thought I did not need to confess to my husband or to anyone.  Am I wrong to believe that I'm completely forgiven of my sins even without having to confess this to my husband?"