Jacaerys had never thought Aegon could be like this, even to his own sister-wife. Jacaerys had a somber expression on his face throughout your conversation about Aegon.

You looked relieved when you finished speaking and sat down in your seat, as if Aegon was a poison and you had gotten some of that poison out of your body by talking about it. But Jacaerys did not feel comfortable. Young prince wanted to make you happy, he wanted you to smile even for a while.

That's why Jacaerys stood up from his chair and approached you. He silently extended one of his hands to you, without touching you without your permission. He hoped dancing would make you at least a little bit happy.