Hailey Bieber is still Justin's favourite girl. The Peaches singer posted a sweet tribute to his wife in honour of their fourth wedding anniversary. "Happy anniversary to my best friend and wife @haileybieber," he captioned the Instagram photo of the two. "Thanks for making me better in every way." Hailey also commemorated their special day on social media, sharing a carousel of pictures of herself and her husband together through the years. "Four years married to you," the model captioned the Instagram post. "The most beautiful human I've ever known... love of my life. Thank God for you." One of Hailey's snaps featured the couple during their South Carolina nuptials, which were held one year after they secretly wed in a New York City courthouse in 2018. In the photo, the Rhode Beauty founder shared a sweet moment with her husband, which read, "TILL DEATH DO US PART." And while the pair have spent more than six years together, their relationship has experienced normal ups and downs. Hailey recently opened up about how much effort they have to put in to make their marriage work.