As with her early relationship with Criston, Rhaenyra's initial relationship with her uncle, Daemon, is speculated about by the fictional historians in "Fire & Blood" but never confirmed. The book suggests she once asks him for "lessons" so that she can seduce Criston, while other sources claim Daemon himself slept with Rhaenyra.
Once again, the TV version shows us how all of these rumours have a kernel of truth but aren't quite the actual story. Daemon flirts with Rhaenyra and whisks her away to see the seedy underbelly of the city. He takes her to a brothel and seemingly has no problem if anyone sees them, and they share a passionate kiss. When they begin to undress, however, Daemon finds himself physically unable to go through with it and storms off, leaving Rhaenyra there. When Viserys later confronts him about the rumours, he offers to marry Rhaenyra; meanwhile, she winds up sleeping with Criston. It's not until many years later, just before their marriage, that Rhaenyra and Daemon actually sleep together.