The Prophet ﷺ said regarding a man who has intercourse with his wife while she is menstruating, "He should give half a Dinar in charity."
حدثنا حسين حدثنا شريك عن خصيف عن مقسم
عن النبي ﷺ في الرجل يأتي امرأته وهي حائض قال يتصدق بنصف دينار
Its chain of transmission is sahih. Khaseef is Ibn Abdul-Rahman Jazari. The hadith, by the route of Sharik from Khaseef, was narrated by Tirmidhi 1:244-245 in our commentary, Darimi 1:254, Abu Dawud 1:109, and Bayhaqi 1:306. We discussed it at length there, along with the rest of the chains of the hadith. See also 2032, 2121, 2122, 2201.