From Sahih Muslim (Hadith 2588):
Umar b Abu Salama reported that he asked the Messenger of Allah (ﷺ):Should one observing fast kiss (his wife)? The Messenger of Allah (ﷺ) said to him: Ask her (Umm Salama). She informed him that the Messenger of Allah (ﷺ) did that, where upon he said: Messenger of Allah, Allah pardoned thee all thy sins, the previous and the later ones. Upon this the Messenger of Allah (ﷺ) ) said: By Allah, I am the most God conscious among you and I fear Him most among you
Reference: Muslim 2588