Reference: Fataawa Ramadhaan – Volume 2, Pages 621-622, Fatwa No.622
Majmoo’ Fataawa Ibn Taymiyyah – Volume 25, Page 263
Question: Regarding a man who intentionally broke his fast in Ramadhaan, then had sexual intercourse [with his wife]. Is he required to make up [the fast] in addition to making an expiation, or is he just required to make up [the fast] without making an expiation?
Response: He is [only] required to make up [the fast].
As regards making an expiation, then he is required to do so according to the math.hab of Imaams Maalik, Ahmad, and Abu Haneefah, but not according to the math.hab of Imaam ash-Shaafi’ee.