I was watching up old episodes too. And every time I do that, Gulaal is a new revelation to me. Gulaal has actually become the woman she is now, in many many steps. Vasant's death was only a beginning, and you're right, she didn't actually retreat into the shell all by herself - incidentally, Kesar himself has had the greatest role to play, albeit unintentionally at all times, then, and now. I was watching those recent episodes of Raman vs Dushyant Sarpanch elections, followed by rumors on Dushyant's win, and Gulaal-Dushy rumor talks - and especially Kesar's heavy duty conflict of emotions at that point.
I think it's gone from Gulaal-Kesar being everything to each other - in equal status, despite the age gap, even a decade ago... to the time when Kesar learns of the Vasan murder truth (which is really just this ironic twist of fate, and neither Gulaal nor Kesar's doing) which causes Kesar to retreat into a shell. So in the way, the closing in, has been Kesar's initiation. He's bottled and brewed for ten long years - during which, Gulaal, despite her repeated means to stay convinced about Kesar's problem being as simple as boarding against wishes - she does realize he's gone too far from her. When he comes back, he's not only impossible for her to fathom, but also shockingly rude. Gulaal in a decade has become this skeleton of the person she used to be, and the only one to change it had to be Kesar - as Talli told him after the drowning incident - but he rips away the merest hope for it, with his initial ways. It doesn't end at that - he gives Gulaal the multiple shock treatment - by spooking her with his masculine evolution, by trying to possess her like his personal doll who he can cherish and mistreat as per his weighing emotion of each day, by mocking and insulting her before family who cares too much, and others who can find pleasure in Gulaal's only support backing out, by making it evident time and again that he trusts anyone, and everyone over and above her.
I think the elections were a huge turning point. When Kesar announced he would back up Raman - Gulaal was this close from nervous breakdown - and then the gossip fiasco over Dushy and her happens ... I think her lashing at Vasant's portrait at that point, complaining so openly to MB, and even telling Dushyant the hard fact of never really finding it in her heart to forgive him - is all a sign of final relinquishing. Personally I think, although the confession actually seals the fact - Gulaal has already closed herself up tight as it gets past that episode. Her not taking a chance at happiness is a long formed change - because she's just been met by repeated betrayal at the hands of those who matter most. Vasant, and Kesar. Her mother misunderstands her, even if for her own welfare, PB misunderstands her to plan Kesar's wedding, Yogesh blames her. Her wall of resilience has, IMO, fallen brick by brick... to give place to the new wall and she can't but hold onto it now in fear and absolute dejection.
It doesn't justify her approach - it only explains its very inception and existence. So we do concur on our point Reemz - it has certainly not been all in the name of Vasant.
I want to say more about Kesar too - he's had his own very complicated history over the same matter. It tears a viewer apart to decide which one to side with! Especially in that post election, gossip time when he goes to PB to ask her about Dushyant and Gulaal (one of the rare times PB actually talks sense, thank god) and then Talli comes cries for Gulaal and Kesar is jolted in the pro-Gulaal mode, only to find Dushyant enter her room ... then Dushyant brings him back from the bus, the Vatt savitri vrat scene totally has Kesar back on track, until he sees Talli with the dupatta. Kesar's conflicting logic has always been crazy equal, and in all fairness to him, he has not been blindly led on, but been guided by strong reasons in either direction. Because the opposite compelling forces have unfortunately always equated and canceled out he's been this utterly torn soul. And when he finally seeks answers from Gulaal - bluntly and plainly, she refuses him that one straight road to redemption, resolution and peace. Not to blame Gulaal - but truly, she owes him that... but the build up to that point has been so full of doubts and wrongs, her human bias takes over and she doesn't relent. It makes me wonder what would have happened if Kesar had been seeking answers from her when they were in their intermediate cordial phase... When Gulaal hadn't already completely shelled up herself, and Kesar was not so walled out and bitter.
But that's the beauty of their agony. It creates such a thick plot, and such wonderfully engaging, thought provoking rich characters.