In fact, the show makes that abundantly clear in episode 3 when Otto (the Hand of the King) suggests that Rhaenyra marry her half-brother Prince Aegon. Sure, King Viserys was shocked at the idea—but only because of their age difference, not because they were related, which, uh, wow!
Otto also hands Rhaenyra an envelope. Rhaenyra opens it and pulls out a folded-up page torn from a book. If that page looks familiar, it's because Alicent read it to Rhaenyra at the beginning of the season while the two sat under a tree in King's Landing.
The two have been dancing around each other since the beginning of the series engaging in a will-they-won't-they dynamic, Episode 7 "Driftmark" not only saw the two of them consummate their love but also faking the death of Rhaenyra's husband Laenor (John Macmillan) together in order to marry each other on Dragonstone.
In the book Fire and Blood, Princess Rhaenyra Targaryen does indeed marry Ser Laenor Velaryon. The pair go on to - officially at least - have three sons.
The age difference between Aegon and Rhaenyra
While Princess Rhaenyra was 17 or 18 years old. Viserys was obviously opposed to this idea just as he had refused to marry Laena Velaryon. While this age gap may not seem significant since Rhaenyra and Daemon too have a 16 year gap between them.
Rhaenyra and Daemon's Marriage
Soon after being widowed, Daemon and Rhaenyra marry each other in secret when he is 39 years old, and she is 23. Their marriage causes a huge scandal at court and another rift between Daemon and Viserys, but it is eventually accepted. The couple has two sons together, Aegon and Viserys.
We have always been meant to burn together." And, in result, she asked Daemon to marry her—and to do away with her first husband. After Laenor was seemingly murdered by his lover, who was paid off by Daemon, the prince and princess wed in an intimate ceremony attended by their children.
Rhaenyra Targaryen (Emma D'Arcy) and Daemon Targaryen (Matt Smith) finally had sex on House of the Dragon. After teasing their deep connection for weeks, making out in a brothel, and flirting their way through King's Landing, uncle and niece at long last did the dirty.
Daemon shows his genuine care and attention to Rhaenyra several times before the two marry. This doesn't take away from the many destructive and inappropriate parts of their relationship, but the books imply that Daemon does love Rhaenyra.
While House Of The Dragon episode 4 showed Daemon was able to seduce Rhaenyra by kissing and undressing her, he couldn't fulfill the act due to impotence.
In 117 AC, Rhaenyra gave birth to her third son, whom Laenor named Joffrey, in honor of Ser Joffrey Lonmouth.
Cooke said that she and D'Arcy” have “definitely” talked about Alicent and Rhaenyra being “each other's first love,” although by this point “too much has happened and too much time has passed to probably even recognize those fledgling feelings.”
Viserys also shares a secret with Rhaenyra, one that she must hold with her, and it's pretty big. He reveals that Aegon Targaryen, the first king to sit on the Iron Throne, foresaw the end of mankind.
In House of the Dragon's season 1 finale, Rhaenyra learns about the tragic death of her beloved son Lucerys Velaryon, after having sent the young boy to deliver a message to Lord Borros Baratheon.
Rhaenyra, recalling the death of her mother in childbirth, refuses help from her maidens as the pregnancy wreaks havoc on her body. Knowing something is wrong, she gives birth all by herself.
While this is a revelation in and of itself, this sequence also highlights the truth of Daemon and Rhaenyra - he is an abuser and she is his victim, albeit perhaps one who does not see herself as a victim.
Later, in episode seven, Daemon tells Rhaenyra that he and Laena were "happy enough" in their marriage. In that regard, there was far more love between Daemon and Laena than there ever was between him and Rhea, even if it wasn't entirely romantic.
Daemon chokes Rhaenyra because he's angry, because he feels she's making the wrong decision, and probably even because she reminds him of his late brother.
While we conjectured that something inside forced Daemon to stop before he took Rhaenyra's virginity, a recent HBO-approved “Inside the Episode” installment revealed that something was literally impotence. He literally couldn't get it up.
After Daemon's first wife dies, he gets together with Laena Velaryon—who was initially suggested as a bride for King Viserys. They have two daughters. Meanwhile, Rhaenyra marries Laena's brother, Laenor Velaryon, and they have several kids.
He chokes Rhaenyra after she starts telling him The Song of Ice and Fire prophecy and learning that Viserys kept secrets from him. Perhaps Daemon's attack was motivated by this perceived betrayal? Part of it also may be related to his dislike of Viserys weakness.
It was clear that Leana and Laenor had a close relationship, and she likely would not appreciate her uncle choosing this moment to make a statement while her brother grieves. Daemon laughs at this moment because Vaemond is choosing this moment to guilt Rhaenyra for having children with Harwin Strong (Ryan Corr).
In "King of the Narrow Sea", Rhaenyra seduced Ser Criston after she herself was denied by her uncle Daemon (Matt Smith). She and her paramour spent the night together, and she was warm towards Ser Criston afterward.
We last saw her find out the truth in "We Light the Way" that Rhaenyra lost her virginity to Ser Criston Cole (Fabien Frankel).