Sayyiduna Ubayy bin Ka'b (may Allah be pleased with him) said: O Messenger of Allah, when a man has intercourse with his wife and does not ejaculate (should he perform ghusl)? He (peace and blessings be upon him) said: "He should wash what touched the woman, then perform ablution and pray."
Hadith Referenceالسنن الكبرى للبيهقي / كتاب الطهارة / 770