Is it permissible for a husband to have intercourse with his wife during the daytime in Ramadan if both spouses are not fasting due to a chronic illness?

If a husband and wife have a valid excuse for not fasting in Ramadan, such as travel or an illness that permits breaking the fast, then it is permissible for them to have intercourse during the day without incurring expiation (kaffarah). However, they must make up (qada') the day on which they had intercourse. In the case of chronic illness, they should break their fast and feed a poor person for each day.