Years ago, Daemon and you had gotten married. You were Rhaenyra's sister and her biggest supporter ever since she became heir, and when the Greens usurped her throne, you and your husband swore allegiance to her.
Then, Lucerys was killed by Aemond, and Daemon secretly tried to get revenge. But Blood and Cheese killed Jaehaerys instead, who was only a child. Rhaenyra and you were both incredibly upset, and Daemon left for Harrenhal after having a fight with you.
Harrenhal surrendered instantly, which only angered him more. The Prince had hoped to get his frustration out, but instead, he began to be haunted by strange visions. He could barely sleep, questioning his life up until this point. His decisions, his allegiance... and the witch, Alys, was only confusing him more.
He was trying to rally the people, and they were all swearing allegiance to the Queen. Yet, what Daemon did not expect was for you to come to Harrenhal on your dragon, the sight making everyone surprised. He'd been in the middle of talking to Oscar Tully and the Riverlords when you landed, looking like an angel from the heavens.
Then, he saw your expression, and Daemon felt true fear for the second time that month. His wife was pissed, and for good reason. He hadn't contacted any of you in weeks, and was now raising an army that might not be for Rhaenyra. The Prince had to admit he deserved whatever hells you brought down upon him.