There is no difference whether the intercourse was with one woman or with two. Thus, if he has intercourse with the first at the beginning of the day and with the second at its end, without having made expiation for the first, then only one expiation is due from him.
The same applies to one who is required to abstain if he has intercourse; and if someone has intercourse while healthy, then falls ill, becomes insane, or travels, the expiation is not waived. ...
His statement, “The same applies to one who is required to abstain if he has intercourse,” means: just as expiation is due from a fasting person who repeats intercourse or commits it once, it is also due from one who is required to abstain if he has intercourse.
This has several cases. One is where testimony establishing the beginning of the month is given during the day, while a man had intercourse with his wife earlier that day before knowing that the month had begun. He must make up that day and must also offer expiation, because he was required to abstain on that day. For this reason, the jurists say that it is disliked for a person to have intercourse with his wife on the thirtieth day of Sha'ban, lest testimony be given during the day, after which he becomes liable for expiation. This view is weak, because Allah the Exalted says:
“So now have relations with them and seek that which Allah has decreed for you. And eat and drink until the white thread of dawn becomes distinct to you from the black thread.” [al-Baqarah: 187]
And because the Messenger of Allah, peace and blessings be upon him, said: “When you see it, then fast.” (1)
Another case is where a man is travelling and has broken his fast, then arrives in his hometown. According to the school, he is required to abstain, even though this abstention does not count as a fast. If he has intercourse during it, expiation is due from him, because he is required to abstain.
Likewise, if a person is ill and permitted to break his fast, and he has done so, then Allah grants him recovery and the illness for which he was permitted to break his fast passes away, then according to the school he is required to abstain. If he has intercourse, expiation is due from him.