even if he marries kusum in original novel he never does it for feeling but just coz he wants kumud to be happy so at the end of the day its all about kumud and ways to keep her happy which saras desperately wants to do
as for kusum she likes saras from day one and will readily take him if offered to her even second hand by her didi kumud...kusum knows saras is for kumud ,she knows he loves her too but she is like those patient girls who wait and watch and at the end get rewarded too out of banovalence, which kumud will do at the end :(
whatever it may be all i know is that the story is all about saras and kumud who keep making sacrifices just to make each other happy...though we all know there real happiness lies in each other