The Boston Celtics player turned 30 on Saturday, and received several birthday messages from the Kardashian-Jenner family.
Khloé -- who shares 2-year-old daughter, True Thompson, with Tristan -- began by writing that "the ones that are meant to be are the ones who go through everything that is designed to tear them apart."
"They come out even stronger than they were before," she added, before thanking Tristan for "showing me everything you said you would. For the father you are. For the best friends I have in you."
Khloé noted that she's "thankful that I can do absolutely nothing with you and it feels like everything," before adding that she hopes he knows "today and everyday how loved you are by me and so many."
"I can't wait for all the memories. This is when life starts getting good," she concluded. The Good American founder and Tristan rekindled their romance last year amid quarantine following the athlete's multiple cheating scandals.
Kris Jenner also gave Tristan a birthday shout-out on her Instagram page, writing in part, "You are an amazing son, brother, dad, friend, partner and uncle Tristan to all the kids and we love you very much!!!!!"
Kim Kardashian also posted a selfie of the two, calling the Boston Celtics star her "brother."
"Honestly I’m so proud to call you my brother! I know we’ve been through it but we came out stronger and closer and I’m just grateful that Khloe has a bestie in you!" she wrote in part. "You’re a great dad, friend and dancer!"
Khloé and Tristan's relationship status and future is discussed in the upcoming final season of KUWTK. In sneak peeks they have discussed having another child and even explored surrogacy. In a recent interview, Khloé shared that they made embryos.
"I actually have done IVF about three different times," she said on Sarah Hyland's Ellen original digital series, Lady Parts. "I froze my eggs once already and when I was ready to make embryos with Tristan, I was making embryos."
She added that when she defrosted the eggs she'd frozen "none of them survived." Khloé also expressed that the COVID-19 pandemic altered her timeline for a second child.
"My plan was to have kids closer in age, but now with COVID and everything, my plan's been a little delayed," she shared. "But I definitely do want more kids."
For more on Tristan and Khloé, watch below.