What they have shown - Mauli goes to Rajdeep's house, Nandini is happy about getting married (At least she looks happy), then she goes to bring tea for Mauli and Rajdeep, Rajdeep being the jerk hits on Mauli and Mauli tells Nandini about it, then Rajdeep points out that Mauli is jealous of Nandini's husband, her big house, the lavish lifestyle Nandini will have and Mauli won't hence Mauli is lying to separate them and Nandini believes Rajdeep over Mauli, obviously believing that Mauli is jealous of her frivolous things, she didn't think for once why Mauli would accuse Rajdeep? I don't know about family pressure because I don't think it was shown that Nandini was forced by her parents and if it was then Nandini didn't tell Mauli about it for Mauli Nandini believes that Mauli is a jealous cunning person who's plotting to separate Rajdeep and Nandini.
Still Mauli knew that Rajdeep is not a good guy for Nandini why didn't she go back after one month or a year so let's look at this logically Mauli cleared Central Pre-Medical Test after 12th standard, in 12th standard she must be what 17 years old, it's not clear whether Mauli qualified right after her HSC exams or she waited one year for it, in any case let's say she was 18 when she qualified, after it she must have moved to a medical college out of Uttar Pradesh considering Kunal is from Mumbai and Mauli-Kunal met in college, so it's common sense that he didn't come to Lucknow for his MBBS, so Mauli was not in Uttar Pradesh for 5 years and even if she visited it must be for roughly a few weeks... So are you telling me that an 18 year old girl who's studying to become a doctor, lives in another city will leave everything, waste her life after a friend who accused her of being jealous? How much can we expect from an 18 years old?
After years when Nandini came back in Mauli's life, what did Mauli do? Mauli became the only hope for Nandini to come out of an abusive marriage, remember before meeting Mauli, when Nandini dreaming about telling Rajdeep that she's pregnant, she wasn't happy when Rajdeep said that he'll divorce her, she was afraid because she didn't have a place to live, after Rajdeep kicked her out of his car in road, if it wasn't for Mauli Nandini wouldn't have a place to live, Kunal did not come to help her on his own, Nandini called Mauli and Kunal picked up the phone at last it was Mauli who helped her.
So I find this absolutely ridiculous that people want Mauli to take care of Nandini, people wanted that Mauli leaves her dreams of being her doctor and destroy her life to protect her friend who doesn't even care about her, and Nandini is not a 10 month old baby, she is responsible for her actions, she was responsible when she chose to live with Rajdeep, she is responsible when she fell in love with her friend's husband and at the end of the day both of her decisions have adverse effect on Mauli, Mauli met Kunal when Nandini left her now when Nandini is back Mauli will lose Kunal