All perfect praise be to Allah, The Lord of the Worlds. I testify that there is none worthy of worship except Allah, and that Muhammad is His slave and Messenger.
{And due to them [i.e., the wives] is similar to what is expected of them, according to what is reasonable.} [Quran 2:228]. Sharee'ah ordered that both husband and wife have to treat each other kindly, and placed rights for both to treat each other. Sexual intercourse is one of these rights; it is a shareable right for both of them. As such, it is obligatory upon each of them to seek to keep the other chaste. The wife’s rejection of her husband’s desire for having sex violates the Sharee'ah, and renders her sinful. Al-Bukhaari and Muslim narrated on the authority of Abu Hurayrah that the Messenger of Allah said: “If a man calls his wife to bed and she refuses, and thus he spends the night angry with her, the angels curse her till the morning.”
The wife’s positive response to her husband in some intimate relations does not give her the right to reject sexual intercourse if he has the desire to do so. Being in no need of sexual intercourse does not give her the right to prevent her husband from this right.
Her husband should clarify the matter to her in a good way in light of what we mentioned. He can also seek the help of some people who could positively influence her.
Allah knows best.