Home is where the heart is.
"It's incredible to think how much life can change in a short period of time," the 39-year-old star began his caption. "Yesterday was our 18 month anniversary and I love this girl more and more by the day!"
The HGTV personality also took a moment to discuss their whirlwind romance and how quickly things progressed.
"I came home with @heatherraeyoung after 4 days of dating," he shared, "she moved in, and we never looked back. She has exponentially improved the lives of everyone in my family. Everyone said I was crazy but here we are engaged almost two years later. She's our rock, our best friend, and my hunny bunny. We love you to the moon and back."
Tarek closed on a sweet note, writing, "Can't wait to take more photos like this in fun places like New York City! I can't wait to continue to build this life with you. You make me a better man."
Back in October, the 33-year-old Selling Sunset star revealed she and Tarek officially "locked in a wedding date and location!!" That same month, the Orange County real estate agent opened up about his and Heather's wedding plans during an interview with Daily Pop.
"We're down to California or Mexico, so two locations," he said at the time, "and we're thinking either May or October."
While the two are certainly used to being on-camera, Tarek admitted they're both leaning towards keeping their big day private.
"We filmed the proposal and it was spectacular and it was a special moment," he explained. "When it comes to the wedding, right now, we're leaning towards not filming it just because we don't want any distractions. But who knows? I don't know."
He added, "I'm just ready to spend the rest of my life with her."
The pair announced their engagement back in July, with the Netflix star posting, "The Future Mrs. Tarek El Moussa!!!!" Tarek cheekily posted, "She said yes! #FlippingHerLastName."
"Tarek thinks of everything," Heather told E! News about the proposal. "He is so detail-oriented. He knew exactly what I would want for our engagement... He made everything so special for me."
As fans of the Flip or Flop star know, this will mark Tarek's second wedding. He was previously married to Christina Anstead, however, they decided to end their relationship in 2016. And by 2018, they finalized their divorce. They share two kids together, Taylor El Moussa, 10, and Brayden El Moussa, 5.
Back in July, Heather expressed just how much it's meant to be part of Tarek's family.
"I'm grateful for so many things right now," she told E! News at the time. "I'm grateful for Tarek for bringing me into his life and trusting me with his kids and giving me a family. I'm so happy. I'm so fulfilled."
Tarek added, "I went through some hell the last six, seven years of my life and today I'm a new man. I hit rock bottom. I found myself in some lonely, dark places and today I'm in love. We're just going to do everything we can to build the best life possible."