Zaid bin Khalid (may Allah have mercy on him) asked Sayyiduna Uthman bin Affan (may Allah be pleased with him) that if a person has intercourse and semen does not come out. He replied: He should perform ablution as he does for prayer, and wash his private part. Sayyiduna Uthman (may Allah be pleased with him) says that (this) I heard from the Messenger of Allah (peace and blessings of Allah be upon him).
Hadith Referenceاللؤلؤ والمرجان / كتاب الحيض / 198
Hadith Gradingمحدثین:«صحیح»
Hadith Takhrij«صحیح، أخرجه البخاري في: 4 كتاب الوضوء: 34 باب من لم ير الوضوء إلا من المخرجين»
Brief Explanation
All these narrations pertain to the early period. Now, after intercourse, ritual bath (ghusl) is obligatory whether ejaculation occurs or not. Imam Nawawi rahimahullah states that there is consensus (ijma‘) of the Ummah that ritual bath becomes obligatory due to intercourse, whether semen is emitted or not. Mawlana Abdur Rahman Mubarakpuri rahimahullah states that this is the truth and correct position. (Tuhfat al-Ahwadhi: vol. 1, p. 100, Raaz)