Well, Hrithik Roshan and Kareena Kapoor have worked together in the past. They made four movies together: the first was a huge flop and the second was a huge success, the third was pretty decent, and the last was a huge disaster.
Hrithik Roshan and Kareena Kapoor :
Of course, I mean Yaadein, Kabhi Khushi Kabhie Gham, Mujhse Dosti Karoge, and Main Prem Ki Diwani Hoon. Personally, I did not like three of these films; the worst was, of course, the terrible MPKDH, but Kabhi Khushi Kabhie Gham and Yaadein were pretty horrible to watch too. But nothing can touch MPKDH in terms of terrible.
As for why they haven’t worked together since then, a big part of the reason is because Hrithik Roshan is one of the most selective actors in Bollywood. He’s done very few movies in his career (compared to other stars), so if you don’t really make a lot of movies, there’s not much scope for working with a more prolific actress, right?
Second, around the time of the Main Prem Ki Diwani Hoon, rumors circulated that the two were dating; Those rumors were not dispelled even when Hrithik Roshan married and Kareena Kapoor married Shahid Kapoor. So if those rumors have any credibility, then it could be argued that this is why Hrithik and Kareena haven’t worked with each other. Perhaps, just to avoid lewd rumors that could pose a problem in their personal lives.
But I think a bigger reason is that they haven’t had too many exciting offers to work together on projects that appealed to both of them. I heard there was a Sanjay Gupta movie in 2015 that would have brought them together, but that didn’t happen (probably Kaabil). So we’ll have to wait and see if they ever work again.