Aishah (may Allah be pleased with her) says that Abu Bakr al-Siddiq (may Allah be pleased with him) never broke an oath until Allah revealed the expiation for oaths. Then he said: Whenever I swear an oath and then something else is better than it, I give the expiation for my oath and do the better thing.
Hadith Referenceالسنن الكبرى للبيهقي / كتاب الأيمان / 19863