The "Flip or Flop" star, who is 37, announced the news in an Instagram post Friday.
"Ant and I have made the difficult decision to separate. We are grateful for each other and as always, our children will remain our priority. We appreciate your support and ask for privacy for us and our family as we navigate the future," Christina's social media post reads.
Last September, the couple welcomed their first child together, a baby boy named Hudson London.
"Ant and I are so excited to welcome Hudson London Anstead into the world. Our hearts are SO full of love and joy! 💙 Our healthy baby boy was born this morning- 9/6/19 - 7 lbs 7 oz 19.5 inches long," Christina wrote on social media at the time.
The "Christina on the Coast" star split from her first husband, Tarek El Moussa in May 2016. Their divorce was finalized two years later. The exes share two children -- daughter, Taylor, 9, and son, Brayden, 5. El Moussa recently got engaged to his girlfriend, Heather Rae Young.
Meanwhile, Ant, a native of the United Kingdom, shares daughter, Amelie, 16, and son, Archie, 14, from his first marriage to Louise Herbert.
"Oh, no. We're done," the HGTV star told the outlet. "We're done. We're done. We're definitely done!"
Christina also opened up about her first divorce in an interview with People in 2018, admitting that she suffered a period of darkness after the two made the decision to split.
“I felt like I was drowning. I was doing whatever I could to stay above water and just get through the day," Christina told the outlet.