Sotah, Chapter One, Mishnah Two
Yesterdays mishnah taught that a husband cannot bring his wife to drink the Sotah waters unless he has first warned her not to seclude herself with a certain man. Todays mishnah teaches what constitutes warning and what constitutes her transgression of his warning, such that she is brought to be tested.
1) How does he warn her?
2) If he says to her in front of two [witnesses], Do not speak with that man, and she spoke with him, she is still permitted to her husband and permitted to eat terumah.
3) If she entered a private place with him and stayed with him a time sufficient for her to be defiled [by having sexual intercourse with him], she is forbidden to her husband and forbidden to eat terumah.
a) If [her husband] died, she performs halitzah but cannot contract yibbum.
Section one: The husband is overly strict in his warning. He suspects that she may be having an adulterous affair with a certain man, so he warns her in front of two witnesses not to even speak with this man. The mishnah teaches that even if she speaks with this man, she is not considered a Sotah. She is still permitted to her husband and, if her husband is a priest, she may still eat terumah. A man cannot prevent his wife from speaking to other men.
Section two: However, if he warned her, and she entered a secluded place with that man, then she is a Sotah, meaning a woman who must be tested before her innocence can be established. Since, she is now under the presumption of being an adulteress, she can no longer have intercourse with her husband. This is according to the rule that adultery forbids a woman from returning to her husband. If she is a priests wife, she can no longer eat terumah, since she may no longer be permitted to remain his wife. The woman is still his wife, but the normalcy of their marriage has ceased and therefore, to be strict, the halakhah forbids them to continue to act as man and wife. The fact that she still is his wife is evident from the last halakhah of the mishnah. If her husband died without children and she had a brother, she can no longer undergo the Sotah ritual. She is still required to have halitzah with her husbands brother, because were she to have undergone the ritual she may have been found to be innocent, in which case the marriage would have returned to normal. However, she cannot have yibbum, because she may have actually been guilty. A wife prohibited to her husband as a Sotah is also prohibited to her yavam.
Note, that this last halakhah is the means by which the mishnah teaches that she is still married to her husband and that the fact that she is prohibited to him and cannot eat terumah are stringencies lest she is actually guilty.