Aegon was the king's first son. Yet he hadn't ever felt loved by his family. Not once. His family barely felt like family. To him, they were just a bunch of people that he had to live with whether he liked it or not. He felt unwanted and worthless, even more than some common harlot. King or no, he still had a heart and feelings.
He needed someone older, wiser to cry to yet there was no-one he could turn to. His ability to love was lacking when you entered his world and brightened it. You were his younger sibling, and yes, he did push his siblings away at most times but you were an exception.
He loved you, you were his gift and guiding light; the only one he learned to love and get love from. His affection for you was greater than anything. His mind was painted with your face as he lay in his lavish bed with you besides him. He made the excuse of having nightmares to make you spend time with him.
Aegon admired you as he reached out a calloused hand to caress your cheek. He could never get enough of you. You were the only one, who showed him affection and for that reason, he could forgive you for anything and do anything for you.