According to Indian law, Shivika and Rikara marriage is illegal. Rumya marriage is legal because they had a community marriage. But in Gul mata's universe, Shivika and Rikara are married, while Rumya marriage is legal. Gul could have shown Rumya taking a divorce, but I guess she was just in a hurry to end the Rumya track, and winded it up in just one scene. One reason can be that CVs wanted to keep the back door open for Soumya if Ruvya are not accepted in the show. If Soumya would have taken divorce from Rudra, then there would have no reason for her to return back to OM.
So if Bhavya is not accepted by the audience, then Rumya marriage will be brought back into focus.
I think it's better not to accept any logic in Gul's show. Anything is possible in Gul mata's universe 😆
She can make any of the couple's marriage legal and illegal at any point of time in this show.