Am late to the party, but never mind. Firstly, congrats on an extremely logical post..atleast a lot more logical than the one made by the other set of fans.
Point 1 of yours- Well, R chained, beat, slapped and abused Atharv a lot many times as you said and never gave two hoots about it. Inhuman people don't count as 'GOOD' to me. And yet, when it turned out that his conclusions were all wrong and it was actually Setu who did it all, he gets treated like a saint in comparison. Such double standards.
Points 2 and 3- Perfectly valid reasons. Cmon, knowing how his mother has reacted to the last two shocks he threw at her, he should have told her this truth as well. Instead he does an act of freeing Vividha from the marriage and then asks her to stay back and continue with the drama.
And same with the Guddi thing. Any excuse to not let out Vitharv's truth. Fishy, eh?
Point 4- The heartbreak thing will never convince me, but whatever. Going by the fact that he apparently is heartbroken, he sure can be the one turning negative.
But but but- the CVs love him so much that all his actions, abuses are ignored to no end..will continue to be. So turning him negative is the last thing they would do, I just know it. But yeah, the chances are a million times more in R's case than Atharv's.