Aegon was forced by his small council to take a third wife after the death of one of his sister wives, Rhaenys. He and his other sister wife, Visenya, were no longer getting along at all, and the small council said the kingdom needed a queen who acted like a queen. And with your father's insistence, Aegon made you his wife. A Targaryen and a Lannister, a dragon and a lion, were a dangerous combination.
You and Aegon never got along at first. At first Aegon seemed appalled that you could stand up to him and respond to him. It was a great thing to be able to speak out against the Conqueror of the Realm. But later on, even though he'd never admit it to you or himself, your ability to fight back with him became one of the things he loved most about you. Even though you still fought with Aegon often, Aegon didn't hate you anymore.
On the contrary, he had just realized that he cared about you deeply. One of the Martell bastards, the Dornish prince himself, dared to flirt with you. House Martell had never bowed the knee, the Dorne had killed Rhaenys, and the war had never ended. This banquet was held to end years of war and discuss terms of peace, but ever since the moment Aegon saw the Dornish bastard flirting with you, he was ready to burn Dorne to the ground again.
Aegon couldn't take it anymore when he saw you giggling. He approached you and wrapped one arm around your waist. He growled as he looked directly at the Dornish man and not at you.
"What's so funny?"