Khloe Kardashian is missing brother Rob Kardashian Credit: Charles Sykes/Bravo/NBCU Photo Bank via Getty Images

Rob Kardashian is gaining confidence and becoming less reclusive since he started dating girlfriend Blac Chyna, but sister Khloe Kardashian isn't celebrating the fact. 

On Thursday, February 18, the 31-year-old Kocktails With Khloé presenter shared a sweet throwback photograph of herself and her brother embracing in the past, with a short but poignant message: "It's simple..... I miss you."

It's simple..... I miss you 😫😫😫

A photo posted by Khloé (@khloekardashian) on

While Rob appears to be doing great since he got together with Chyna, hitting the gym and emerging from his self-imposed exile, it seems other family members are still struggling to deal with the situation.

And Khloé, who Rob lived with for much of the time he was struggling to deal with his weight and depression, is evidently finding it tough to adapt to her brother's new situation.

"Khloé feels majorly betrayed by Rob after she always stuck up for him," a source close to Rob told Us Weekly shortly after news of his new romance emerged. "She feels like this is a major blow to the family. Nobody in the family likes it.”

But although Khloé is struggling to deal with her brother's life choices, there's no doubt many good things have come out of his relationship with his makeup artist girlfriend.

Earlier on Thursday, the duo were snapped emerging from a gym together, with Rob looking slimmer than in the past. And later on Thursday, the loved-up 28-year-old beamed a huge grin as he posed in a Snapchat video with Chyna, looking happier than he has in years.

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