What is the ruling on my remaining with my wife who allowed a strange young man into my house three times, while she asserts that he did not touch her?

The wife committed a grave error by allowing a man to enter upon her, which constitutes a squandering of Allah's right and her husband's right. The husband must urge her to sincere repentance, warn her of Allah's punishment, and explain the Sharia rulings to her, while monitoring her behavior without ill suspicion, supplicating for her guidance, and encouraging her to associate with committed women.