I think Ayaan and Humeira will get engaged in the future and this time with Ayaan's agreement (he finds out about Humaira's love, and her sacrifice makes him develop a soft spot for her). Then the engagement breaks because he finds out that Humaira is a liar (how?? I don't know, maybe she manipulates him after she can't take being away from him anymore... but I'm just going with the synopsis). Ayaan vows never to love anyone. Asad knows about this.
Around the same time AsYa will only separate..or they might have an incomplete divorce. And in this time, Ayaan-Zoya become really good friends, he starts liking her. Asad finds out about Ayaan's love for Zoya and he assumes that Zoya too loves Ayaan because they get along so fabulously. That's when Ayaan's sacrifice comes into play.
It's going to be hard to digest watching both Ayaan and Asad marry Zoya (even if I forget about consummation) and then on the last day of the show watching everything hunky dory between the three of them. The least they can do to satisfy a viewer like me is to leave the ending realistic..meaning that Asad and Ayaan never become as close as they currently are and that awkwardness always remains.