From what you are saying, it seems to me that there are several explanations for his behavior. One is that parents want his best friend to be a chaperone, presumably to prevent sexual activities; and that I get the feeling that he might have ambivalent feelings about the nature of the relationship. He does not want to make it exclusive, and the constant presence of his b/f would be giving you such a message. He seems to never want to be alone with you. If this is not your idea of a sizzling male-female relationship, I suggest that the two of you communicate alone (obviously face-to-face is best, but phone could work), each stating aims and desires. You might as well find out what each wants, then make appropriate decisions.