It's a long story with a very simple moral- Shukla is not capable of treating anyone with respect. He likes his women agreeable and doormat-ish, who will support him when he spews shit about other contestants and their families.
I did not watch much of the initial episodes, but, basically shukla is allergic to house chores. Their fights started from there. Then he couldn't digest seeing her with strong supporters, especially men. They had a huge showdown, where he sl*t shamed her. Ugly remarks were thrown from both ends.
Rashmi, is not perfect but she keeps her dignity above the show. So despite the blatant favourism towards shukla, she managed to stick to her stand and hasn't switched sides. They are on talking terms at the moment, but she doesn't want to see his face outside the show.
Also, shukla is for some reason wierdly obsessed with her. He is often seen as provoking, mocking or demeaning her, infront of Rashmi as well as behind her back.
The end!