Is it permissible to recall or imagine the caresses and fondling that used to occur with the ex-husband before the divorce, when needed?

Your ex-husband is a stranger to you. If a woman imagines things with a stranger, or a man imagines such things with a strange woman, the ruling is clarified in Fatwa no. 37509. This difference of opinion applies if it is done intentionally. As for thoughts that come to mind unintentionally, and the person strives to repel them, there is a consensus that they will not be held accountable for them. The imagination of a husband by his wife and a wife by her husband has been previously explained in Fatwa no. 36519.