Yeh dekho... Mujhe kya Mila..
This theory I have seen on Instagram... Credit to the original one.
Theory after today's episode -
I think Arjun and Mukhi are together in this game plan, Arjun may have told this plan to Mukhi but not Purvi. Sakshi is the real killer of Daksh, but no one has the proof against her and no Body knows who killed Daksh, but Arjun got to know that and her motives that's why he made a plan with Mukhi to keep safe Purvi and Kids from Sakshi, so Arjun will make fake marriage papers to show case everyone that he is married to Purvi and ofcourse purvi doesn't know about this. After marriage kids and Purvi will stay in Arjun's house and they'll be safe, here Mukhi will do the drama of heartbroken person and Sakshi will take advantage to come closer to him and Mukhi will accept her as per the plan, so sakshi will be overconfident about that her plan got successful and now she won Mukhi but that's not true as Mukhi and Arjun wanted this only to happen, now taking advantage of Sakshi's trust Mukhi will find out the evidence against her that she is the real killer ofDaksh. After they'll successfully find out the evidence then they'll reveal the motive of their plan and that's it sakshi will go behind the bars
Credit to original writer... I have just posted!