Abdullah bin Umar (may Allah be pleased with them both) narrates that a husband kissing his wife and touching her is considered an act of touching, therefore whoever kisses his wife or touches her, ablution becomes obligatory upon him.
Hadith Referenceمسند الإمام الشافعي / كتاب الطهارة / 61
Hadith Takhrijاخرجه البيهقي : 1/ 124 وفى المعرفة السنن والآثار له (172) ، والدارقطني: 1 / 144 - ومالك في الموطأ الطهارة، باب الوضوء من قبلة الرجل امرأته.