Is the wife considered sinful if her marital relationship continues physically separated from her husband, knowing the possibility of him watching pornography and her inability to confront him, and her desire to stay for the sake of raising the children, and is God's pleasure linked to this situation?

Your continued presence with your husband in this state is not considered a sin as long as you do not refuse to obey him. It is not obligatory for you to offer yourself to him; rather, what is obligatory is to obey him if he calls you. The husband must fulfill his wife's right to the bed, which is one of her greatest rights. Sheikh al-Islam Ibn Taymiyyah issued a fatwa stating the obligation for the husband to have intercourse with his wife in a reasonable manner, and that this is one of her most emphasized rights. The soundest opinion is that it should be according to her need and his ability. We advise you to strive for reconciliation, be patient, and supplicate frequently, so that Allah may guide your husband and foster affection between you.