Beauty is in the eye of the beholder, you see him as gorgeous and he sees you as gorgeous too, not everything is in our bodies/faces, he loves you for who you are like you do him - he might even think the same if a hot guy looks at you too!
With the other girls though, let it go, it’s life that there’s going to be other girls around but that in no way means that he fancies them or would ever make a move on someone else. What do you like about yourself? Show that off, feel good about it, don’t beat yourself up. Self confidence takes time but the main thing is to not compare yourself, no one else can be you x