Toxic relationship or maybe a mental issue?

So I’ve been with my boyfriend for about 2 years. Recently, with all the stress and anxiety I’ve been going through I’ve been making quite a few mistakes. These mistakes aren’t really horrible mistakes but when they occur he just tells me that I’m retarded because instead of him directly telling me what I did wrong he makes me try to figure it out and it takes me quite a while for me to figure it out. When it comes to watching educational videos with him he gets upset when I don’t understand things right away and again, interpreting certain things takes me quite some time. When these scenarios happen he just says that I’m being stupid on purpose and that I’m intentionally trying to hurt him when clearly that’s not my intention at all. He also keeps telling me that he can’t be with someone who’s stupid/ retarded. I’m wondering if maybe I have a mental learning blockage or if there’s anything mentally wrong with me for not getting to understand things that most people would be able to get in seconds. Lastly, I ask if it’s my current relationship that’s just not the right person to be with. Maybe I’m not at the same level as he is and it’s now starting to take a toll on this relationship.

It could be both. In my opinion, it’s a toxic relationship with an abusive partner. Even if you are a retard, your abusive partner chooses to be with you. So who’s the real retard?