Is a woman sinful if she refuses her husband's intimacy due to psychological or physical exhaustion, and do the angels curse her in this case, and is she obligated to fulfill his desire at all times?

A wife must obey her husband if he calls her to bed, unless there is a legitimate excuse such as illness, menstruation, an obligatory fast, or harm that would befall her. It is not permissible for her to refuse merely due to a lack of desire, as a severe warning has been reported for a wife who refuses without an excuse. The Prophet, peace and blessings be upon him, said: "If a man calls his wife to his bed and she refuses to come, the angels curse her until morning."