He could write your biography
He knows more about you than anyone else and it’s not just because the two of you spend so much time together. He actively takes an interest in what makes you tick and genuinely enjoys learning about you. That means your plans, aspirations, and your childhood.
What this should tell you is that there is a depth to his feelings for you and that he is focused on you. Besides, learning about you teaches him how to make you happier so don’t be scarce with the details.