With Mishti being in relationship with Veer, it is still the same. But bcos she is engaged they can show her move on, except before it was marriage. Y do they want to show these commitment breaking concepts? She genuinely liked Veer and engaged to him and breaks it for Ruhaan.
Even if he is he won't be shown more this time. They played smart by not even having the actual cheated person in pic with other love triangle in the focus. Also Kunal seems to have lot of fan following so they will support him. Many might think since there is no marriage, it is ok to cheat and move on. No commitment.
Actually Rohan even if he doesn't have more screen space deserves to be in the montage. Since he plays key role. If he is not there, there won't be the chaos of commitment vs lust. Pari is not needed.