In Weatherford's The Secret History of the Mongol Queens he mentions that Genghis Khan's son was accepted in court despite his questionable paternity because he was known to be the son of Temujin's wife. Was this a common sentiment? Did the Mongols have the same conceptions about chastity, monogamy, and sexuality that the West did?
First of all it would be false to claim that Jochi's paternity caused no issues. While he was afforded respect and authority as Genghis Khan's first born son it appears that the questionable parentage was raised as a point against him by Chagatai when Genghis Khan's was choosing his successor.
That said the Mongols attitudes towards sexuality and sexual purity were distinctly different from contemporary European ones. It was common for Mongol men who could afford it to have multiple wives. Of these one would be considered the chief wife who continued the bloodline, only Genghis Khan's sons from his first wife were considered as sucessors, although they all had separate accommodations; and visitors often commented on the surprising lack of disputes that this arrangement engendered. Furthermore Mongol women retained the right of divorce, and remarriage, something that was considerably more different for both sexes at the time.