“Sebastian just smiled. â€œI could hear your heart beating,â€� he said softly. â€œWhen you were watching me with Valentine. Did it bother you?â€�â€œThat you seem to be dating my dad?â€� Jace shrugged. "Youâ€™re a little young for him, to be honest.â€�â€œWhat?â€� For the first time since Jace had met him, Sebastian seemed flabbergasted.”
— Cassandra Clare,