As for what Ahmad ibn Muhammad ibn Isa narrated, from Muhammad ibn Sahl, from his father, who said:
I (narrator) asked Abu al-Hasan عليه السلام, peace be upon him, about ‘a man who came to his wife (for intimacy) in the month of Ramadan while he was travelling.’ Imam عليه السلام said: “There is no harm.”
Ali Akbar al-Ghaffari
Tahdhīb al-Aḥkām fī Sharḥ al-Muqniʿah, vol. 4, p. 311