Is a wife forbidden to her husband if a fornicator had intercourse with her in the front or back passage, and is she obligated to inform her husband of the incident, or should she conceal it with God's concealment?

A wife's adultery, whether through the front or back passage, does not invalidate the marriage contract, nor does it make the woman forbidden to her husband. She must conceal her sin and not inform her husband or anyone else about her transgression. If she repents sincerely, she should forget the past and not surrender to whispers (of Shaytan), because repentance erases sins, and "the one who repents from sin is like one who never sinned."