Reference: Fataawa Ramadhaan v2 p610 no.604
Fataawa as-Siyaam p67
Question: If a man had sexual intercourse with his wife during the day in Ramadhaan, is one kaffaarah sufficient for both of them [together] or is it imperative that there be a kaffaarah for the man and another for the woman?
Response: Some of the scholars are of the opinion that the kaffaarah is sufficient for both of them [together]. [However], that which is correct is: If the wife consented [without force], then a kaffaarah is required of her just as is required of her husband. If, however, she was forced, then a kaffaarah is not required of her except to make up the fast for that day. This is because one who is forced is excused as Allaah سبحانه و تعالى says:
And the Messenger of Allaah ﷺ said:
