I am telling my points based on all your comments.
The position in which Kalyani is in, she won't be able to support Revathi's love. Definitely Pavithra is magnanimous here. Throughout the serial Pavithra has shown lot of courage. It is possible Pavithra could persuade Kalyani and Mohan to accept the love of Revathi. One point here is SK's father is determined for the marriage of SK and Revathi. What will happen if he schemes something? Forgetting love is not easy either for males or females. We have seen males go into depression once they are forced to forget the love as the girlfriend leaves. It is quite possible Revathi could go into depression.
As far the position of Kalyani, she has to be loyal to her ibn-law family. Ideally we could expect Kalyani accepting Revathi's love. But she has to deal with MM, Padma and Mohan who are all not so broad-minded. For a wife, to be able to take independent decisions in her life with her husband and her in-laws, it seems the only way is to be like Sudha. Sudha could understand the needs of her husband Puvi and do the needful according to them and as Puvi is convinced her attitude helps him, he favors her and neither forces her to be loyal to the family though we also see, Puvi and Sudha reasonably loyal to Puvi's family. Thulasi is in her studies and is no way able to take financial responsibilities and so she could not assert her independence. TA neither supports her whenever he believes his ambitions could be fulfilled with the help of persons whom T didn't like. (I am not supporting TA. Just telling the facts.). Again while Sudha had support of her father, Thulasi didn't. She had to face troubles from Padma. Deepa has criminal husband. How the director could get the Deepa character clean is in his skill.
Kalyani's position is trickier than Thulasi as not only herself but her sisters are also dependent on Mohan and (Padma!). If only MM, Padma and Mohan are more understanding, Kalyani could find things better. But that is not the way in the World. And as Kalyani and her sisters are orphans also, they are at the mercy of Kalyani's in-laws who are the only solace for them presently.
Edited by maha2us - 15 July 2013 at 3:42am