Eighteen years down, a lifetime to go! Chip and Joanna Gaines just hit a special marriage milestone! The "Fixer Upper: Welcome Home" stars have now officially been husband and wife for 18 years. Their anniversary landed on Memorial Day, and Joanna marked the occasion with an Instagram tribute the next day. She shared a compilation video from what looked like an anniversary trip to Mexico, set to James Taylor's song of the same name. Joanna captioned the video, "18 years. Thankful to be on this adventure with you—happy anniversary @chipgaines."