Alright so after watching the last few episodes and all the mess going on with the property papers, Fahad being in the middle of all this mess, Shazia's dad playing everyone and being a part of it, and NOW her father blackmailing Suraiya, I think this is what they might end up doing.
You know how Shazia's family is hell bent on getting Gowhar into the house and marrying Zain, well what if they find out the papers have been stolen (or taken back because you know don will find out) and since Shazia's dad is all a part of this, as a way to blackmail them they will tell Abdullah family that the only way they can save face and get themselves out of this mess is if Zain marries Gowhar. Shazia is a little schemer so I won't be surprised if she comes up with this or becomes a part of it.
Hence, Zain has to have a second marriage to her and this is how Aaliya ends up leaving the house and his life and goes back home because this is one thing she can't live with. This is when Zain starts realizing how good he had it, how perfect Aaliya was for him because he'll see Gowhar's nasty habits and be disgusted and see that she's just a golddigger.
Or this whole track with Ayaat might lead to something big too. There's so many ways they can go through with this. Because we all know Aaliya is going to leave and that too when Zain has fallen in love with her. Maybe Aaliya begins to believe that he is having an affair with another woman, since he leaves to "dehli" when he's taking Ayaat back home. She starts suspecting him. Hmm any ideas?