Rituraj's truth is out in the open for Sweetie, even though she already knew about it. So why stay with him? Why even stay in Haveli? She needs to make use of her education and stand on own two feet. She needs to want to do it though otherwise even Nimki can't help her. Anaro can't understand Sweetie's pain, Anaro has a family of her own and she is happy with it, it only scares her when her family gives her less importance because that's all she has. Sweetie's life is stuck it hasn't moved forward since she got married.
So Rambachan knows the truth, why allow Nimki to stay there? Nimki is only putting up a pretence to save hurting him further.