Ketubot, Chapter Three, Mishnah Five
The final clause of the previous mishnah stated, The rapist must drink out of his pot, meaning that the rapist must marry the woman whom he raped. Our mishnah elaborates this law. As an aside, we should note that even though he must marry her, the woman is of course given the right of refusal, as is the father.
What is meant by he must drink out of his pot?
1) Even if she is lame, even if she is blind and even if she is afflicted with boils [he may not dismiss her].
2) If she was found to have committed a licentious act or was unfit to marry an Israelite he may not continue to live with her, for it is said, And she shall be for him a wife(Deut. 22:29)a wife that is fit for him.
Section one: The rapist must marry the woman whom he has raped, even if she has some physical handicap that makes him not want to marry her. He lost his right to decide whether or not he wanted to marry her when he raped her.
Section two: However, he may not marry a woman who is halakhically forbidden to him. After all, if this were not so, a man could rape a woman and thereby allow himself to marry a woman who would have otherwise been forbidden to him. The mishnah lists two types of such women. The first is a woman who has committed a licentious act. This refers to a woman who committed adultery after he had married her. As is always the case, a husband may not continue to live with his wife if she had committed adultery. If in this case, the rapist married the woman and then she committed adultery, he may not remained married to her.
The second example is a woman who is not allowed to marry an Israelite, such as a mamzeret or a natinah. If he raped such a woman, he may not marry her, and if he did marry her, he must divorce her. Similarly, if he was a kohen and he raped a divorcee, he is not allowed to marry her. This halakhah is derived from a midrashic reading of the words And she shall be for him a wife, which are read by the rabbis to mean that the woman must be halakhically fit to be his wife. If she is not, he is allowed to divorce her.