I think they were friends only because of Himanshi and with her gone there’s nothing holding them together.
Shefali is manipulative but that’s her game so she should play like that. Asim takes time to understand things but now he does.
Asim hasnt trusted Shefali in a long time and he even admitted the same to Himanshi. Shefali on the other hand before any differences with Asim did tell Bhau and Arti that She was only friends with Asim because of Himanshi.
I think it’s mainly a power struggle between them that has led to the dissolution of their friendship and their friendship might have never been strong in the first place and were only together because of Himanshi who they both loved.