The 34-year-old singer has been with the professional dancer and choregrapher for just over a decade, and they got engaged in December 2017.
Announcing the news on Instagram, he shared a photo of them wearing their wedding bands before adding, “We did it” plus a black love heart and ring emoji.
Richards shared the same photo on her own profile and wrote: “Husband and Wife” before using emojis to signal she was on “Cloud Nine” and adding the hashtag #MrandMrsMerrygold.
The couple share two sons – Grayson Jax, four, and Macaulay Shay, two.
Earlier this month, they celebrated their 10th anniversary together with Richards posting a gallery of images of them from throughout the years.
She wrote: “10 whole years of loving of you – of fun laughter and making forever memories.
“Right now it might all seem A LOT but let’s face it wedding planning really isn’t our strong point but it will all be worth it when that day comes (in about 5 minutes) when I finally get to become your wife.
“I cannot wait to be Mrs Merrygold and make a whole lot more memories as your wife! I love you favourite, with every piece of me. Now let’s go make this official.”
Merrygold rose to fame as one quarter of the boy band JLS, who found success after finishing as runners-up on the 2008 series of The X Factor.