@bold: The question right now isn't really of acceptance...the question is about hurt and anger. I don't think either Anika or Shivaay are consciously thinking about acceptance regarding this marriage...both of them are mainly grappling with immense hurt...and in Shivaay's case there is more anger too. He's basically been kinda off his rocker since the ONS MU...he feels betrayed by Anika on some level but doesn't even want to acknowledge that he feels that...cuz acknowledging that would mean he also has to acknowledge that he's hurt, that she affects him...and that's when he starts unraveling. He's hurt because he had started to trust her, started to admit to the "jo humaare beech"...now all that's gone for a toss. Ofcourse he won't stop to introspect that he was busy getting ready to marry Tia in the background regardless😆...he still feels hurt by Anika and to counter that, he clings to the other extreme...becoming absolutely stone-hearted, stone-faced again and repeating his claims over and over about how none of this means anything.I almost feel like he needs to keep repeating that also because he doesn't want to COPE with the magnitude of what he's done to Anika...it's easier to dismiss it, deny it, pretend it hardly happened rather than process the level to which he fell in doing this...cuz each time his brothers bring it up, there is that slight chink in his armor even as he tries to coldly dismiss their emotional pleas.In Anika's case also, they are keeping the dialogues mainly focussed on her hurt over what has happened to her, the blow she's been dealt in such a horrible way...the actual reality of the marriage might be acknowledged on a subconscious level vis a vis the MS but on a conscious level, I don't think Anika's mind is there at all...she's moving through the rasams and events like a robot...her heart and mind aren't there...she's still in trauma...which is why she barely even reacts much when Shivaay repeats to her yet again today that he doesn't believe in this marriage and the divorce will come through again...she has this matter of fact expression on her face like she isn't even surprised by what he's saying...it's only when he says, "Kuch hua hi nahin" that she reacts.There is a pain in the silence b/w them because even though the debate is all about the acknowledgement of the shaadi right now, neither of them is willing to bring up the real source of the hurt...that they both feel let down and hurt by each other...the shaadi is just a prop and a technicality everyone is dancing around...the crux of their relationship is bigger than that and they both know, but they won't say it lest the other accuse them of actually caring.
I know both aren't consciously thinking about acceptance atm, but I feel that an unconscious level both have accepted this marriage to some degree. More so in the case of Shivaay, which is why he feels the need to constantly clarify that this marriage with Annika is only a farce and not real (defensive Billu at his best). On reception night, he got wedding flashbacks immediately prior to announcing Tia as his wife. Although he had already planned to announce Tia as his wife, but even here he was doing it half-heartedly.
The flashbacks sorta got him back on track and in typical Billu fashion, he announced Tia as his wife in front of the world in his mission to get a kick out of Annika assuming that she'd get super depressed over this. His claims about doing all this to maintain family honour was all in the background here but of course he'd use that to justify his doings but that has more to do with Billu justifying to HIMSELF that Annika doesn't bother him the slightest and he's doing everything for his family. All of this works on a feedback loop and further fuels his anger and hurt and then some more anger and hurt caused by the fact that the reason for his anger and hurt is HER.
Then to cope with all of this, he resorts to his defense mechanism like you said. Becoming stone-hearted and getting defensive at every given opportunity. For Annika, she's also accepted the marriage but it has more to do with her belief in the institution itself rather than her accepting Shivaay as husband. So she's unconsciously accepted the fact that she's married now but she wants nothing to do with Shivaay...if that makes sense. This would explain her behaving like a robot and doing all the post-marriage rasams.
In the episode in Annika's house, Billu was also upset nah when she said she doesn't accept this marriage? Notice how Annika is hardly bothered when he does the same. This indicates that in the future he's gonna run circles around her in desperation of wanting her to acknowledge him as her husband and not vice versa.
Your last para is spot on! Couldn't have said it better myself. :)