All perfect praise be to Allaah, The Lord of the Worlds. I testify that there is none worthy of worship except Allaah, and that Muhammad, sallallaahu ‘alayhi wa sallam, is His Slave and Messenger.
Certainly, the wife has rights on her husband. Amongst them are that he treats her kindly and keeps her chaste. Jurists have stated that it is obligatory upon the husband to have intercourse with his wife according to her need and his ability. For more benefit, please refer to the Fataawa 86618 and 88304.
If your husband treats you harshly and does not have intercourse with you without a valid and legitimate excuse, then he is falling short in his duties towards you. It is good to be patient with him, however, you should speak to him about this kindly and leniently, make a great deal of Du‘aa' (supplication) to Allaah The Almighty to make his heart tender towards you and to make him fulfill his duties towards you.
On the other hand, imagining that you are having intercourse with another man, for example, if it is just a crossing thought that you are resisting, then there is no blame on you for that. However, thinking about it intentionally and continuing to do that is one of the steps of Satan and a means to temptation. Islam has considered the yearnings and desires of the heart as one of the means of Zina (i.e. unlawful sexual intercourse) as stated in the Hadeeth narrated on the authority of Abu Hurayrah that the Prophet, sallallaahu ‘alayhi wa sallam, said: "Allaah has written the very portion of Zina which a man will indulge in. There will be no escape from it. The Zina of the eyes is the [unlawful] look, the Zina of the ears is the [unlawful] listening, the Zina of the tongue is the [unlawful] speech, the Zina of the hand is the [unlawful] grip, the Zina of the feet is the walking (to the place where Zina is intended), the heart yearns and desires and the private parts approve all this or disapprove it.” [Al-Bukhari and Muslim]
Finally, if you fear temptation and harm, you may think about divorce if it is better for you and search for another man to marry. As for your children and parents, their affair is left to Allaah The Almighty; He will protect them and take good care of them.
Allaah Knows best.