Comment of my underwear size

Marisela
So, my boyfriend the other day made a comment about my underwear size, he said that they were too big and went on to say "why don't you get smaller underwear" I replied with, "this is my size" and I have been self conscious about my body ever since. He made the same comment when he looked at a thong I wore. What do I do. How can I not let comments like this get to me.