My boyfriend for eight months been hanging out at his house and his best friend is there most of the time and I was just wondering how I no for sure if he likes me likes me... but as much fun as I have with him and stuff it can't be more then friends because he's my boyfriends best friend

I doubt he sees you like that, as he's being a good friend by spending time with his best friend. Perhaps you should distance yourself, before screwing up your relationship and their friendship.

I agree..
Maybe he's just there to be with his friend, and not because of you... you should just stay friends with him because you don't want to break their friendship & your relationship

Its no shame in liking, or being attracted to others, while in a relationship. That's natural to all humans. What does matter is, how you handle those feelings, that is something you can control. Choose your actions wisely.