VATICAN CITY -- Pope Francis has offered some Valentine's Day advice for a lasting marriage, saying the recipe for success lies in saying three simple words: "Please, thanks and sorry."

Francis told some 10,000 couples gathered in St. Peter's Square on Friday that expressions of courtesy, gratitude and contrition go a long way toward conserving and enhancing love over time.

Francis has on several occasions met with young couples to give them advice before embarking on marriage. The need for such counseling is a theme he's expected to elaborate on at a major Vatican meeting on the family next October.

Francis joked that we all make mistakes and that no one is perfect: "The perfect family doesn't exist, nor the perfect husband or wife. Let's not even talk about the perfect mother-in-law!" (AP)