Is expiation obligatory upon the wife whose husband had intercourse with her several times during the daytime in Ramadan, due to her ignorance of the ruling, and is one expiation sufficient for all instances?

Intercourse during the daytime in Ramadan is forbidden, is one of the major sins, and unanimously necessitates making up the fast and expiation (kaffarah). However, for someone who was ignorant of the ruling, there is no expiation according to the more preponderant opinion. But knowledge of the prohibition along with ignorance of the obligation of expiation does not waive the expiation.

Therefore, if intercourse occurred without ejaculation and you both believed it to be permissible and not to invalidate the fast, then no expiation is required of you. As for intercourse with ejaculation, making up the fast is obligatory, and expiation is obligatory for the husband. Regarding its obligation upon you, there is a difference of opinion, and it is more prudent to pay it.

If you are unsure about the number of days on which ejaculation occurred, the default is two days, so you may build upon that assumption.