Acknowledging that the COVID-19 pandemic has aggravated some family problems, Pope Francis has encouraged married couples to seek help and always remember three key words in a marriage: “Please, thanks and sorry.”

Francis penned a letter to married couples that was released on Sunday, a Roman Catholic feast day commemorating Jesus’s family. It came halfway through a yearlong celebration of the family announced by Francis that is due to conclude in June with a big rally in Rome.

In the letter, Francis said lockdowns and quarantines had forced families to spend more time together. But he noted that such enforced togetherness at times tested the patience of parents and siblings alike and in some cases led to difficulties.

“Pre-existing problems were aggravated, creating conflicts that in some cases became almost unbearable. Many even experienced the breakup of a relationship,” Francis wrote.

He offered his support to those families and reminded parents that the breakup of a marriage is particularly hard on children, who look to their parents as a constant source of stability, love, trust and strength.

“The breakdown of a marriage causes immense suffering, since many hopes are dashed, and misunderstandings can lead to arguments and hurts not easily healed,” Francis wrote.

“Children end up having to suffer the pain of seeing their parents no longer together.”

He urged parents to keep seeking help to try to overcome conflicts, including through prayer. “Remember also that forgiveness heals every wound,” he said.

He repeated a refrain he has often used when meeting with families and married couples, listing the three most important words in a marriage: “Please, thanks and sorry.”

“After every argument, don’t let the day end without making peace,” he wrote.