By IB standards, where most "logic" is a stretch anyways, I think Sumo's justifications aren't that far fetched.
It's been so long that many seem to have forgotten just how QUICKLY Rumya were phased out and Bhavya forced into the show overnight.
Sumo and Rudy were both confused about where their relationship stood...at one point, they seemed all for their marriage, then overnight suddenly they were like "we're just friends"...lol instead of guiding them properly, Shivika just had one argument around it and story randomly switched gears...so the neglect was very much there...made all the worse by them taking one look at Bhavya and pretending like she's instant family.
Neha really acted well in today's epi and lent some shades to Sumo's feelings...she feels hurt and betrayed by the family including Shivaay for how quickly they all forgot that she was married to Rudy...no matter the forced "friend-zoning" that was done to the Rumya story, the way the family forgot the Rumya marriage has always been weird to say the least.
And the way I see it, more than ruining Shivaay, she wants to DEFUND the Ruvya wedding right now😆...na rahenge paise, na hogi shaadi seems to be her logic...LOL so jaise bhi ho, I'm game for a Rumya plotline cuz Neha has SOLID screen presence and Rumya still have more meat in their storyline than the supposed "in love" Ruvya getting married right now...lol