Just watched the latest episode guys.
To be honest, I feel bad for Katha. I know many people were saying that Katha should have been more direct when it comes to Ehsan. But when someone is behaving in a way which makes you uncomfortable (such as Ehsan touching Katha), the shock almost paralyses you and you don't know what to do. I'm sure Katha must also have been both confused and uncomfortable as she has considered Ehsan to be a friend, and she does not want to make the whole situation awkward. So to be honest, I can emphasise with Katha.
Yes she has been a 'lioness' (as some people mentioned) when it came to Viaan. But that's also because perhaps she feels that she has a right over him to outwardly express her opinions. In other words, I think in a way, ironically she feels more comfortable with Viaan than Ehsan.
I also feel that her indirect rejection to Ehsan (when she said that Arav is the only man in her life) was also effective. But what I don't understand is why she goes to Ehsan's house for dinner, when there is an air of discomfort in between them now. That's the part that I find unrealistic, as we women usually tend to stay as far away as possible from men who make us uncomfortable.