"The sexiest day of my life was 5yrs ago when Johnson came into my home #MAY21," Simpson wrote. "We are awesome."
Simpson, 34, revealed that she met the former NFL pro thanks to a setup from her friends Lauren and Bret Harrison. "Fortunate for these two @laurenz422 and @bretharrison for the unexpected intro #MAY21 #JOHNSON," she captioned a pic of her and Johnson dining with their pals.
The entertainer was a bridesmaid in the couple's March 2012 wedding and Lauren used to be her assistant.
After the couple's anniversary evening, Simpson started snapping pics of their adorable kids, Ace and Maxwell. "Back home to this crazy kitten ballerina," she said of her daughter.
As for Ace, she wrote: "Wild man Ace Knute #MAY21 #JOHNSON I am so in love with my family."
The Dukes of Hazzard star was first reported to be seeing Johnson, 35, when the two were caught kissing on Italian island of Capri in July 2010. In July 2014 Simpson and Johnson were married in Montecito, Calif.