Muwatta Malik:Divorce:Hadith 1317
وَحَدَّثَنِي عَنْ مَالِكٍ، عَنْ نَافِعٍ، عَنْ عَبْدِ اللَّهِ بْنِ عُمَرَ، أَنَّهُ كَانَ لاَ يَعْزِلُ وَكَانَ يَكْرَهُ الْعَزْلَ ‏.‏

Yahya related to me from Malik from Nafi that Abdullah ibn Umar did not practise coitus interruptus and thought that it was disapproved.