The woman with whom I studied confided in an elder that she'd had lovers during her marriage (Why on earth did she do that?). The elder told her that even though it was well in the past, she had to tell her husband. Her husband was holding a glass when she told him and he crushed the glass with his hand and started to beat her. Great advice, Brother C.
I had had affairs too, but the last t hing I felt I needed to do was tell an elder, much less my husband. I'd had enough of "confession" as a Catholic.