In your situation, you have confessed your sin to your wife, but not all the details, and you lied about some of them. She has forgiven you and expressed her forgiveness in terms of covering even what she does not know. She does not wish to know more. You, however, are bothered by your lies and want to confess them to her, hoping the confession will give you peace.
You ask where Paul instructs us to confess our sins after we have been saved. As a student of Paul, you probably know that Paul never speaks in terms of confessing sins after we are saved. Nor does Paul ever instruct us to confess our sins before we are saved. Paul simply never teaches about confessing sins. Rather . . .
We all are lost in our sin. We all deserve death. But we have been ransomed by the Jesus of the Bible. Our chains have been loosed. Sin has no more power over us. Read Chris’s poem by clicking the link below.