If Sid was better off alone, then KK would also 'handle' him in no time.
As Anushka told Gayatri, no father wants to see his daughter as a widow. Her being with Sid protects him from immediate harm and buys him time to find more proof against KK.
KK himself alluded to Anushka fighting like a tigress with Vedant, stopping him from hitting Sid during engagement. Rao wanted to murder Sid but KK spoke about this instance and said he didn't know his daughter had a fighter trait in her, to protect Sid.
Edited by peachesnplums - 7 years ago