My boyfriend thinks I m stupid, how should I respond?

If you re really good at math, then you know in order to succeed or learn something new you have to know the basics. Well, I managed to get through school without mastering what I needed to know and it caught up to me. I ve been practicing lately and I m okay with re-learning but my boyfriend is making fun of me and calling me names, referring to me as a "space cadet or airhead". And offered to help but is causing me to feel extremely uncomfortable and got mad when I asked if he could help me and the way we approach problems with less aggression.