The 33-year-old shared a photo of the happy couple in front of balloons that spelled out "I [heart] U."
In the caption, she included "When a woman is loved correctly, she becomes ten times the woman she was before," a popular quote used in meme around the internet. She also added, "Thank you my love" and a heart emoji.
The post was Kardashian's first Instagram post in 10 days. Her previous post had two photos of her showing off her baby bump at 29 weeks on Feb. 6.
On Feb. 4, she congratulated her younger sister, 20-year-old Kylie Jenner, who announced the birth of baby Stormi Webster that day. The photo showed the two sisters before Kylie gave birth.
"Congratulations My Sweet Kylie! What a magical ride it's been! I'll miss you bumping along with me," Kardashian wrote. "Never in a million years did I think we would do this together but it's been that much more special because of it. God is so great!! He had His plan all along! I love you little mama... love big mama."
After months of speculation, Kardashian finally confirmed her pregnancy in December with an Instagram post showing off her baby bump (and Calvin Klein sports bra).
"Tristan, most of all, Thank you for making me a MOMMY!!! You have made this experience even more magical than I could have envisioned! I will never forget how wonderful you've been to me during this time! Thank you for making me so happy my love," she wrote in the Dec. 20 announcement.
In a recent app post, Kardashian described sex with Thompson during her pregnancy.
"In the beginning, sex was the same," Kardashian wrote. "As I got into my third trimester and started to get bigger, it became harder to have sex and a little more uncomfortable and limiting. Tristan is amazing and would never make me feel different in any way, but I'm sure it's uncomfortable for a man to have sex with a pregnant woman too."
Kardashian admitted that she can get "uncomfortable and insecure," adding, "Also, you can't move the same, so you kind of feel useless. But you just have to improvise and do the best you can."
According to Us Weekly, Kardashian wrote in another post that she knew early on in her relationship with Thompson that he was the one.
“I knew Tristan was the one very quickly — I have never felt so comfortable or so safe with someone,” Kardashian wrote. She said they took their relationship "very slowly" and “had very in-depth conversations.”
“Tristan was so forthcoming with his life, as I was with mine," Kardashian revealed. "It was really reassuring to feel that someone had the same belief systems as I did. We spoke about religion, children and our families.”
Photo credit: Instagram/ Khloe Kardashian