Smash his face against a wall and make him ugly... Orrr... appreciate that everyone is beautiful in their own way, and that he chose you. You have to be beautiful in some way for him to want to be with you. Like it's not ALL looks. Maybe you're pretty with a personality to compliment it to make you beautiful. I mean I'm not the most attractive thing in the world but I have some confidence... and a really weird personality that seems to attract some strange folks :) Good luck, and remember you're beautiful. Just believe it.
Just gain more confidence, even if you think 'your not pretty enough for your boyfriend', you have pretty everywhere surrounding you! God makes everyone that way! whether outside, inside, both, or just a little harder to notice on the outside. We all have our pretty side, and our ugly side.
He obviously thinks u r beautiful!!! If not u wouldn't be dating. Also the #1 most attractive quality in a person is CONFIDENCE in yourself. If u master that u will never feel not good enough again. Btw I bet u r beautiful