Rob Kardashian has been "really affected" by the way his former partners have treated him

Speaking on the second part of E!'s 'Keeping Up With the Kardashians:

The Final Curtain' reunion special, Khloe said: "It's not so much about physical appearance.

"It's about how he felt internally about some of the women in his life, and how they treated him or how he felt they might have used him to get to certain areas or levels.

"I think that really affected him, because my brother is such a lover, and has the most incredible heart and personality.

"I think he's just getting stronger. I think you have to get heartbroken and learn from your mistakes, and I think he's just stronger and feeling better to be around, and be more vulnerable or exposed."

Khloe noted that Rob - who has four-year-old daughter Dream with Chyna - is "feeling really good about himself right now, and he's working really hard on himself" but admitted he hadn't felt ready to participate in the reunion because it meant he would have to "address the parts that made him want to take a break."

For now, the 34-year-old star is dating again and working on co-parenting with Chyna, while the rest of the family are determined not to let their relationship with his former fiancee - who is suing various members of the clan over the cancellation of spin-off series 'Rob & Chyna' - have any impact.

Khloe said: "We can only imagine how hard that is for him, and I know he feels really guilty about that, so none of us ever make him feel bad about it.

"Dream is honestly one of the most incredible little girls in the entire world.

"We never blur the two... We respect that Chyna is the mother of Dream, and we'll always respect that that's her position. So we never try to [let that bleed through] and make Rob feel more guilty. 'Cause that's out of his control."