Is the ignorant wife excused if her husband had intercourse with her during the daytime in Ramadan, and she did not know about the obligation of expiation? And is expiation obligatory upon her alone, or upon both spouses, and how are the days and expiation to be made up for her?

First: You are not excused for your ignorance regarding what you did, as you knew that intercourse during the daytime in Ramadan is forbidden and invalidates the fast. Your ignorance of the necessity of expiation is not an excuse.

Second: Thank Allah for His forgiveness, and frequently seek His forgiveness (perform Istighfar) and do good deeds that expiate sins. You must make up the days you missed. As for the expiation (Kaffarah), it is more cautious to perform it to avoid scholarly disagreement, though it is permissible to follow those who rule that it is not obligatory for women.

Third: According to the view that expiation is obligatory, some scholars hold that a single expiation suffices for all days if they are of the same type. If you act upon this view, it would be good.