I have a theory regarding V-P marriage ... which most of you are already aware...
Aaj ka FB revealed that by the time V thought of adopting Vinu, he was not married to P, but was friendly with her.
It is P who asked him to adopt Vinu.
Going by previous predictions of mine... most probably P genuinely changed / repented her deeds as was seen in the fight episode. Everyone at CN saw her transformation. Maybe started working at an orphanage in Nagpur. Where she met this child, but doesn't know he is Vinayak (as of now). Hence, V was calling her Pakhi and was okay with her. 
V met the boy on the mission and formed an instant connect. It may or may not be that its the same orphanage or that they shifted these kids to P wala orphanage.
He does say, jab se mila hun.. ek khichav sa hai.... jab bhi udaas hota hun isse aake milta hun... so this is not his first meeting with the boy... its repetitive.
P says "tum" adopt kyun nahi kar lete. So V has most probably adopted him alone and has sole custody.
(I dont think they will show married for adoption as that would be another IBF complaint)
In this process, if P is working there, she takes V to meet him regularly... which is what Ash alludes when she said to P tumne bahot kuch kiya. Saw him recovering quickly. P also says to V, I saw you smiling.
So Vinu definitely helped V get over the loss.
Another point I had made earlier, Vinu calling P Mumma might be to do with this... like in many films/shows we have seen, the kids at orphanage call their caretakers Maa or Mumma... Might be P has that nomenclature at orphanage and Vinu but obviously continues with that.
V recovers quickly and Ash sees this... also notes how P sort of engineered this... believes P has changed (first convo post leap)
Hopes that maybe getting these two married will give maa baap ka pyar to Vinu and since V is hell bent on not moving from Sai, marrying P will rekindle past flames as they had a history, something better than nothing.
V doesn't agree but Ash manipulates him and gives some kasam.
V begrudgingly agrees but maybe mentions to P that he cannot fulfill the responsibilities as husband. Starts calling her Patralekha to signify this. Which P knows, hence she is okay with the two bed system, but Ash ka repeated prodding is giving her hopes now.
Ash is seeing this and looks like her manipulation is working, hence she is continuously pushing P towards V.
Why do I think it is Ash? and why this may work?
V has no proper justification so far as to why he married P? Doesn't look like manipulation on her end... or his softening towards P. So it has to be an external effect. The kind of V they are showing in FBs, looks like he doesn't want to live and wont listen to anyone, not even BK, but he stopped his dangerous missions on Ash's kasam. So why cant she give him another one?
If they have been consistent about something is V has never denied Ash anything.... so him agreeing to it because of her fits well.
Also, it takes away the culpability from him and will get him forgiveness from Sai.
They have always maintained this fact that Sai considers Ash a mother figure.... even in Shruti track, when Ash was horrible to her, Sai accepted everything, forgave her when Ash didn't even say a sorry.
Sai will easily accept the excuse that V married P because Ash asked him. 
It also fits in the future CN drama where there will two teams. I see BK siding with Sai-Saavi.
Since Ash has pushed P towards V, P can turn around and guilt trip Ash. Also like we discussed, Ash will be inclined to favour P over Sai since she knows P will never leave V like Sai does.
V cannot come out of this relationship until P and Ash free him. So the makers can extend this drama as much as they want.
He will be shuttling between the two and may have to beg his own mother for his happiness.
I know its very twisted and cringey, but Ash, V, Sai ka character can very well do this...
It also keeps P/Aish in the show for long.
Only when Vinu ka parentage is revealed can the balance tilt in Sai's favor.
The only good thing in all this is V-P marriage is fairly recent.. maybe just few months old even and totally invalid
. Hence the distance.
As for V flinching at the mention of marriage, if this is recent, he hasn't yet processed it neither he wants to because he was forced. But P has got hopes so she tries to get close to him, aided by Ash's manipulations. That abla behaviour is to influence him. It is also her usual tactic to pretend that she leads an unhappy life. This is what she always does with V. Nothing new in that.
In all this, if P is negative (which we are assuming), probably she doesn't know initially that he is the same Vinayak, but while completing the adoption process, comes across the details, like maybe his age, photo taken on his day of arrival, his clothes or something, that may link him to actual Vinu. But then she sees this as an opportunity and hides the info from everyone. Hence the 'dark history' caption... that only she knows he is the same Vinu... and then her nirjala vrat, nange paav and all the concern for him makes sense, because this is the same Vinu she carried for 9 months and yet he doesn't reciprocate. This adopted Vinu is also fairly old, so he probably knows he is adopted, hence doesn't have much attachment to anyone except V because V has that connect (atoot rishta mentioned by Sai in delivery scene) and is caring to him.
If P is truly changed, she will quietly move aside when Sai ka presence is known.
But we know how P works, she is at a stage where her hopes are high, for her, Sai ka arrival will be "haath main aaya lekin munh tak nahi gaya". She will turn negative again, will plan and plot against Sai, will be aided by Ashwini to some extent and eventually only some other factor like Ninad/Omi ka illness, V ka continued attachment to Sai-Saavi, Saavi ka paternity will make the situation turn. Since she is so obsessed with this Vinu, she might also hide that parentage factor so as to keep the upper hand. The truth will have to come out tumbling during Vinu ka treatment.
They can easily extend this for 3-4 months.... with 2 parivar playing out simultaneously.
There would be situations where Sai will keep coming to CN for sometime (if she has not shifted to Nagpur) and the faceoff happens .... like BK inviting and including Saavi in every function because she is ghar ka chirag, which in turn brings Sai to CN and drama, drama, drama. đ„ł
Vinu has already predicted a jumbo Diwali. 
If they speed it up and show some religious significance, then Saavi can come to CN for the first time in Navratri... 
. Its still 14 days to go.
