I understand your frustration completely. But is there any real marriage between Saalekh ?? What has Alekh ever done for Sadhana as a husband?? He has already disowned her...disrespected her so many times. Sadhana gave him another chance by going back to Rajvansh house after Vasu kicked her out. But no...Mamma's boy preferred to stay in his room and cry.
Does it make any difference by signing the papers ?? At-least she can save someone's life. If Sadhana was interested in money then she would have signed it earlier and got the alimony. Lets give this poor soul a break !! She lost on purpose so that her elder sister doesn't get another depression attack as her self confidence is so low. She became emotionally weak after rememering her good times with her sister. Can't blame her in this case.