The 27-year-old athlete, who's spent his entire NBA career with the Cavaliers since being drafted by the team in 2011 out of the University of Texas, wasn't one of the most well-known players outside the sporting world until he started dating Khloe in the late summer of 2016. But he was considered a solid teammate, and before a thumb injury forced him onto the bench last April, he had the longest-running streak of consecutive games played in the NBA, having played in 447 straight games since his rookie year.
He was more of a local headline-maker than a tabloid target, but he did make a few strange headlines.
In 2014, as Cleveland Scene noted, he had some sportswriters and a chunk of Twitter and YouTube commenters calling for his suspension when, during a pre-game interview courtside, he bent down and kissed Fox Sports Ohio reporter Allie Clifton on the side of her head after answering her question about his planned playing approach for that night.
"Oh, hey!" a surprised-looking Clifton exclaimed as she turned to the camera. "And with that he also said he just goes off the feel of the game, just like he does with interviews, I guess."
While observers raged on her behalf, protesting that it was hard enough for women to work in sports as it is, Clifton handled the fracas graciously, tweeting afterward, "Hey fans @RealTristan13 thing was inside joke & not a big deal. We have a good working relationship. All is good. Can't wait 4 @cavs tonight."
Nothing ended up happening to Thompson (Clifton's tweet, and #MeToo being three years away, probably helped him out there), and local media had much bigger fish to fry. That also happened to be Thompson's first year playing with LeBron James, who had left Cleveland for Miami the year before Tristan was drafted. It was a joyous time in Cleveland.
As far as his relationship history, Tristan was drafted fourth overall right before the NBA lockout in 2011, so he took the opportunity to go back to school in Texas. An article about him in Sportsnet magazine referred to his biggest expense being a "furnished, off-campus apartment he shares with his girlfriend, Whitney, who graduated from UT in the spring and works for a recruitment company in Austin."
Thompson, who signed an $82 million contract with the Cavs in 2015, said at the time that he loved clothes but only owned two suits. And he couldn't wait to actually buy his first car.
"It's the first sign of having money," he said. "Going into the dealership and putting my money down and my name on something."
At some point in 2014, Thompson started dating Jordan Craig, an Instagram influencer who had previously been linked to NBA player Baron Davis and (small world alert) Tyga.
When Khloe met Thompson in 2016 he was expecting a baby with Craig, but that situation actually never proved as awkward as it could have been. Craig opted to take the high road and not make a spectacle on social media or elsewhere about her ex's new girlfriend, and Khloe and the rest of her family basically just rolled with it—being the epitome of a sprawling modern family themselves, they're well aware that life can take unexpected turns.
"As far as [Khloe] knew, there were no negatives," a source told People. "Once she made the decision to commit, she was all in and trusting."
But as it turns out, her mom and sisters Kim and Kourtney Kardashian were reportedly concerned about the potential for her to get hurt—especially because she'd been married to an NBA player before, and Lamar Odom turned out to be a cheater.
On an episode of Keeping Up With the Kardashians last summer, Khloe tells Kourtney, "Tristan and I definitely talk about starting a family. He wants to have five or six kids with me and that's lovely. We could start at one and we could grow from there. But now knowing I'm not on birth control is just like—it's scary. It's like a really big step."
In January, Khloe—who didn't confirm the widely reported news that she was pregnant until she was almost six months along—told Ellen DeGeneres that Thompson was "such a great dad" to his son, Prince Oliver, who is now 16 months old.
After the stories started to pop up about her ex allegedly stepping out on Khloe, Jordan Craig, who also now has a lifestyle blog, took to her Instagram story to write, "If you respect yourself and you respect others, you would never make light of the misfortune of anyone, nor would you feel indemnified when it comes at the expense of others. Wishing peace for everyone."
Khloe of course has her family rallying around her right now. A source tells E! News that Kris Jenner is already in Cleveland with her, having arrived to be there for the birth of her ninth grandchild, and "all of the sisters are dropping everything to be with her."
At one point Kardashian and Thompson bonded over their big families, Tristan being the oldest of four brothers. In 2013 he started the Amari Thompson Fund in honor of his little brother, who has epilepsy, to help families affected by the disease.
"I'm like the big daddy with all of them!" Thompson told NBA.com about his siblings. "I have to make sure I hold them accountable. If my mom texts me and lets me know if they're acting up, I'm going to shoot them a text, because I know what they're weaknesses are. So they either get in line or there's gonna be repercussions."
He's also very close to his mother Andrea Thompson, a former school bus driver originally from Jamaica who's always been her son's No. 1 fan—and who just celebrated a birthday.
"Thank you so much for all of the sacrifices you have made for me and our family!" Tristan captioned an April 1 happy birthday post on Instagram. "Watching your hard work and dedication for our family is what made me the man I am today! I love you soo much and enjoy your day MOMMY."
So he's got at least one fan in his court.
The mother of his second child, however, may be through with him.
Khloe "will obviously never be able to trust Tristan again or look at him the same way," a source told E! News Wednesday. "Her world is shattered. She is in complete disbelief that this is happening. The family absolutely believes it's in Khloe's best interest to end the relationship but will support her either way."