Poor Ashvini! She said that she has always thought of Jayadev as her big brother. That makes marriage between them incest, not preferential endogamy. Sadistic writing indeed.
Now Raghav's second cousin Urmila (his father's mother's brother's daughter's daughter) has been introduced, and as a marriageable woman playing with younger boys, the similarity to Ambika is unmistakable. Is Sunanda going to try to get Urmila married to Raghav?
The internet tells me that in South Indian communities, a man can marry his father's sister's daughter. She is considered a "cross-cousin," just like his mother's brother's daughter. Would a Tamil audience recognize Raghav-and-Urmila as an equally respectable alternative to Raghav-and-Ambika?
For a Marathi audience, however, the two situations are very different. Raghav taking Ambika from the same family that gave his mother Sarasvati to his father Rangarav is respectable because it reinforces an existing donor-recipient relationship between two families. Likewise, Jayadev taking Ashvini from Vishvanath reinforces Vishvanath's family's gift of Jayadev's mother to his father. However, when Rangarav functions as Sunanda's brother, substituting for his mother's family that gave Sunanda to her husband, if Urmila is to be given back to Raghav, that is regarded as an exchange of brides, quid pro quo, which is not respectable. Similarly, when a man's sister marries his wife's brother, that is contemptuously called sāṭa-loṭaṃ - "returning the sarees," as if the trousseau and honorary sarees given with one bride have come back with another bride.
Going on a tangent now... Bhāgavata-Purāṇa, which was written in South India, identifies two of Kṛṣṇa's wives, Mitravindā and Bhadrā, as daughters of his paternal aunts, and Nārāyaṇīyam emphasizes that each of them was his paitṛṣvaseyī (father's sister's daughter), as if to convey a preference for this type of endogamy.
In Harivaṃśa, which is an older text and possibly written closer to the North Indian location of the Śūrasena and Kuru lands, there is no indication that Kṛṣṇa married any paternal aunt's daughter. Kṛṣṇa's wife Mitravindā is identified only as Kālindī (woman from the Kalinda land or daughter of a man named Kalinda) and Kṛṣṇa doesn't have a wife named Bhadrā. In Harivaṃśa, Kṛṣṇa's half-brother Kauśika married his paternal aunt's son's daughter Sutasomā Yaudhiṣṭhirī, Pradyumna and Aniruddha each married his maternal uncle's daughter, and of course, Arjuna married his maternal uncle's daughter Subhadrā. Two of Kṛṣṇa's wives, namely Satyabhāmā and Akrūra's sister (Sundarā?), are his sagotra parallel third cousins - his own father's father's father's brother's son's son's daughter.
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