One thing to note is how Rishabh didn't completely reject her idea or create problems so that she couldn't come to Kolkata. Yes he protested at first but he didnt protest too much if that makes sense.
If he was really involved in the mess himself would he give up so quickly.
Him staying back almost gives him a secure image like he trusts Prerna enough to let her go. Sigh. Always giving her agency. She broke that trust the last time and here we go again.