Should the questioner follow her vision, which guides her to divorce after performing Istikhara, knowing that her marital life is deteriorating and divorce has occurred twice before, or should she be patient for the sake of her children?

Istikhara (seeking guidance from Allah) is legislated for permissible matters and not for prohibited ones. This includes a woman seeking divorce without a شرعي (legitimate, Shar'i) reason, because it is forbidden for her to even perceive the scent of Paradise, as stated in the Hadith. However, if there are legitimate reasons, there is no harm in seeking divorce, but reconciliation should be attempted first, especially if there are children, as family disintegration negatively affects children. The questioner should strive to attempt reconciliation, even by involving family or others. If that does not work and she finds harm in remaining with her husband, then it is permissible for her to seek divorce.