“I heard Abu hurairah say: ‘No, by the Lord of the Ka’bah! I did not say: “Whoever wakes up in a state of sexual impurity (and wants to fast) then he must not fast.” Muhammad (ﷺ) said it.’”
Sunan Ibn Majah Book 7, Hadith 65
← Previous Hadith “The Messenger of Allah (ﷺ) would enter upon me and say: ‘Do you have anything (any food)?’ If we said: ‘No,’ he would say: ‘Then I am fasting.’ So he would continue fasting, then it we were given some food, he would break his fast.” She said: “Sometimes he would fast and (then) break fast (i.e., combine fasting and breaking fast in one day).” I said: “How is that?” She said: “Like the one who goes out with charity (i.e., something to give in charity),and he gives some away and keeps some.”

Sunan Ibn Majah Book 7, Hadith 64 Next Hadith → “The Prophet (ﷺ) used to spend the night in a state of sexual impurity, then Bilal would come to him and inform him that it is time for prayer. So he would get up and have a bath, and I would see the water dripping from his head, then he would go out and I would hear his voice during Fajr prayer.” (One of the narrators) Mutarrif said: "I said to Amir: 'Was that during Ramadan?' He said: 'In Ramadan and at other times.'"

Sunan Ibn Majah Book 7, Hadith 66