It is still very clear Madhu didn't forget what happens between her and RK. She still remembers what RK has done. But she is someone who sees the goodness in others. So she is appreciating RKs goodness and the times he was there for her protecting her.
I agree Jules, Madhu is still not falling for him. She just sees the goodness beneath the man who has destroyed her simple life. Even for an enemy she would not wish something bad to happen. And here is her husband, whether the marriage is complete or incomplete, she is someone who values and respects relations and commitments. And she would not be someone who will take revenge on people.She might try to make a person see where he went wrong but will never take revenge, like she did with RK, when the accident happened.
Mostly Madhu wants this time RK's faith to be back. So for that she is doing everything in her hand to make it happen. But she also knows RK will not like her to donate her blood and save him. But for his mother and the promise she made to RK's mom made her do it. There are enough reasons for Madhu to do everything to save RK's life apart from the reason she is doing this because she is falling in love with him. So for now I don't think she has fallen in love with him. Whatever closeness, bonding they have for now is from both sides, and not only from Madhu's side.
Whatever happened between them, she is grateful for what RK has done for her father and also what he did to save her. So dloing something like this for RK when he was in this situation is a small thing for someone like Madhu, who always bring other's happiness above hers.