<human>: Give me the gist of the text in a nutshell

I've been seeing this guy now for about 6 months and things are great, except there is one major problem from my perspective: I think his best friend is an asshole. 

Even when I first met him he was pretty unpleasant to me which made me feel uncomfortable, but his rudeness seemed to get worse over time and I have never really understood why.

Especially when we're in groups, he likes to call me out on anything from my appearance to something I said that sounded stupid to even just being too quiet. Sometimes when I'm in the middle of talking he'll cut me off, talk over me, or tell me to shut up. I'll admit that I can get quite flustered in these situations so more often than not I don't know how to react. I usually get along well with people and I don't like confrontation (especially meaningless confrontation), and on top of that I don't want to make my boyfriend more uncomfortable. I also feel uncomfortable because usually when he's there we'll be hanging out with my boyfriend's friends who I'd like to win over but he makes me feel degraded in front of them all. I've tried being nice to him, I've tried ignoring him, I've gone off on him a couple of times, but he just seems to make it impossible to feel comfortable in his presence. He doesn't even seem to want to have a normal conversation with me. My boyfriend has apologized on his behalf and told him to stop several times but it's always the same.

We tend to not hang out at his place anymore because of this reason, but I really don't want this to get in the way of our relationship which I value so much. 

Should I change my attitude? Should I just not care? I want to get along with his friends but this is making it really difficult.
<bot>: My boyfriend's best friend is rude to me for no reason to the point where I don't want to be around him; I don't know how to deal with this problem.