Muwatta Imam Malik Book of Divorce, Hadith 98
Yahya related to me from Malik from Nafi that Abdullah ibn Umar did not practise coitus interruptus and thought that it was disapproved.
وَحَدَّثَنِي عَنْ مَالِكٍ، عَنْ نَافِعٍ، عَنْ عَبْدِ اللَّهِ بْنِ عُمَرَ، أَنَّهُ كَانَ لاَ يَعْزِلُ وَكَانَ يَكْرَهُ الْعَزْلَ .