Yahya bin al-Jazzar narrates from Sayyiduna Abdullah bin Mas'ud (may Allah be pleased with him) that he said: "If I went to my wife at night, then deliberately left off the ritual bath until morning came, that would not prevent me from fasting, because I went to her while she was lawful for me."
Hadith Referenceالمعجم الكبير للطبراني / باب العين / 9534