Me and My boyfriend have the same exact problem. Instead if pushing issues sometimes its better just to let him think he is right, its saves you the aggervation of feeling like he’s ignoring your concerns. Which he most def is. IF it is something that is bothering you to this extent and he continues to ignore it you need to be stern and direct.. Explain what bothers you why, and what he can do to help. If he’s not willing to compromise he is unfortunately probably not even worth your time..
As for the girl whose always clinging around and starting shit, if they refuse to see why she is someone you prefer to aviod, they are not only stupid but your boyfriend and his best friend should just hang out together..

Best Regards
Men are tough and clueless lol