Although she was initially flustered by the news that Chen Yu wanted to take her home for the New Year's holiday and the sudden mention of a child, Jounouchi Hiromi soon recovered under Chen Yu's reassurance, after all, she and Chen Yu could no longer be separated.
It wasn't that Jounouchi Hiromi had to be with Chen Yu, but she clearly understood that as a half-dragon, half-human Transcendent, she could never choose a normal person to be her husband.
As for leaving Chen Yu and choosing someone else as her husband then turning that person into the same kind of being as herself after marriage... That option had never been in Jounouchi Hiromi's considerations from the beginning.
Just like Chen Yu initially refused to accept her confession, neither she nor Chen Yu could accept the idea of a stranger entering their lives; after all, Transcendents were different from normal people.