aww. good luck. i had a similar situation. a good friend of mine is getting married in october and since the beginning, she's always asked my opinion on everything (i'm not in her bridal party, but i'm attending the wedding). well, my ex-roommate and ex-best friend (we had living issues among other things), who is one of her bridesmaids, has fought my opinions on everything, counter-opinioning (is that word?) to everything i offered which frustrated me completely. the bride, however, liked all my ideas since we have the same taste.
but anyway, good luck and i hope it gets better. i say, just focus more on your best friend.after all, it's all about the bride.