מצוות עונתה

see the article attached, and these parts written by Maimonides:

Maimonides, Mishneh Torah

Hilchot Ishut – the Laws of Marriage

Chapter Ten, Halacha two:

"Once the arusah has entered the chuppah, her husband is allowed to have

relations with her at any time he desires, and she is considered to be his

wife with regard to all matters. Once she enters the chuppah, she is called

a nesu'ah, although [the couple] has not engaged in sexual relations. [The

above applies when] it is fitting to engage in relations with the woman. If,

however, the woman is in the niddah state [when relations are forbidden],

the marriage bond is not completed and she is still considered

to be an arusah although she entered the chuppah and remained in privacy

[with her husband]."

Chapter Fourteen, Halacha seven:

"It is forbidden for a man to deprive his wife of her conjugal rights. If he

transgresses and deprives her of these rights in order to cause her

distress, he violates one of the Torah's negative commandments, as [Exodus

21:10] states: "Do not deprive [her] of her sustenance, garments or conjugal

rights." If he becomes sick or his virility is weakened, and he is unable to

engage in sexual relations, he is given a period of six months – for [a

woman is

never required to wait] longer for her cnjugal rights then this – in the

hope that he recovers. Afterwards, the prerogative is hers [whether to

remain married] or whether he must divorce her and pay her [the money due

her by virtue of her] ketubah.