my boyfriend called me stupid

Okay so my bf has always put himself above me. He always makes me seem stupid when 1. I have much better grades 2. Work harder in school than him 3. Am pre med and have a harder class schedule. I did a full semester of class this summer and only have two classes right now since i am volunteering, working and getting a nurse certicification. Well my sister just sent me a video of him calling me stupid cause i am taking less classes. The thing is i help him with his essays and hw. Im really pissed rn because ive been telling him he acts like im incompitent. Its not that i believe his comments but it does hurt me because no matter his grades or what he does i never would call him stupid. What do i do?What do i say to make him realize that this is rude? I transferred to community college this year to save money (about $30,000 a year) which would otherwise have been a loan which i have to pay. So in the long run if he says hes gonna marry me he would be stuck with me paying an even bigger loan. i plan to go to medical school i have all these plans but he has made so many insults abour me to me, my friends and his family. How do i get my poibt across?