Parrots curse Sita- story in Padma puran

The story goes thus..

Young Sita is busy playing with her sakhis in their royal garden when suddenly her attention is drawn towards a Parrot couple perched on a nearby tree , these parrots were busy singing glory of Sita Rama , written by Valmiki . Sita is surprised to hear her own story and now wants to hear full story from the parrots, she manages to catch hold of this couple with the help of her servants . She demands to know the whole thing but the female parrot denies saying they don't know the rest of the story and they should be let off, Sita isn't impressed , by now she's a little sceptic and says she will not let them go till Rama comes to Mithila to seek her hand in marriage. The male parrot pleads and asks her to let them go since the female parrot is pregnant and might lay eggs anytime soon. The female parrot pleads saying since they are birds accustomed to live in the wild, her children shouldn't take birth and grow in captivity.. After tireless pleading Sita allows the male bird out of cage and wards him away , seeing this the female parrot is heart broken and gives up her life but before that she curses Sita " just as I was separated from my beloved, you to will bear the brunt of it by being separated from your beloved husband when you're carrying" .

Yatha tvam patina sardham viyujyasi mamitah|

Tatha tvamApi rAmeNa vimukta bhAva garbhiNi ||

The male when it knows of the tragedy vows to come back and be the cause of Sita's separation and drowns in river Ganga and is reborn as the washerman to take revenge and his task is accomplished when Sita is separated from Rama while she was pregnant.

In our puranas, even Gods were cursed at times, but like Ram says, whatever happened, happened for the good of the world.

This folklore prominently forms a part of southern Ramayana's , its also included by skanda puran - southern version and is a favorite story of ntr movies on Ramayana

As far as Sita spending her life serving rishi patnis is concerned, its a total myth and actually the other way round

Uttarakandam VR mentions that in Valmiki ashrama , Sita was alloted separate quarters and valmiki specifically instructs the inmates specially the rishi patnis to take care of her needs ; its only out of humility that Sita must have served rishi patnis not out of compulsion

It is said that Saraswati maa cursed all three Brahman, Vishnu and Shiv when Brahma married Gayatri maa because she was late to the ceremony.

Her curse was that Vishhnu will always be separated from his love very time he takes a human form and that has always happened, with Sita and Radha.