If a man deliberately breaks his fast during Ramadan due to thirst, does he only have to make up for that day, or is he also required to fast for two consecutive months after having intercourse with his wife on the same day? And is the wife only required to make up for that day, or does she also have to fast for two consecutive months?

A fasting person is not permitted to break their fast merely due to thirst. If they do break their fast, they must repent, make up the missed day (qadaa'), and refrain from eating and drinking for the rest of the day (imsak). The expiation (kaffarah) becomes obligatory if intercourse occurs. However, if one fears perishing or severe harm due to thirst or hunger, they are permitted to break their fast out of necessity. In this case, they must make up the missed day, and according to many scholars, they are not required to refrain from eating and drinking for the rest of the day. It is permissible for him to have intercourse with his wife if she is not fasting due to a legitimate Sharia-approved excuse other than menstruation or post-natal bleeding. However, it is not permissible for him to have intercourse with her if she is fasting. In the situation mentioned, the wife erred by allowing him to have intercourse with her, and she owes expiation according to many scholars. The husband erred by desiring intercourse while she was fasting. If the thirst was tolerable, he also owes expiation and must make up the day. Both of them must repent to Allah.