Although Madeleine's marriage to Ed isn't perfect, it seems they've finally reached a good, stable place in their relationship. At the beginning of the episode, Ed, still upset about his wife's affair, asks if they can have a vow renewal ceremony. In his eyes, it will cement their commitment to each other and remind them of the day they got married, which Ed says was full of joy and "so much promise." (Apparently we can assume he never got busy with Tori!)
Madeline agrees to his plans, and after briefly suggesting they throw a big party, she surrenders to Ed's idea of having it be just the two of them and their daughters. They have Abigail officiate the ceremony by the sea as Chloe acts as a flower girl. They all wear flower crowns. It's pretty adorable.