I feel like my boyfriends close friend is trying too compete with me?

okay, so here lately my boyfriends close friend has been constantly trying too hangout with him. well when i started realizing this was about 2 weeks ago, me and my boyfriend were together at my house, hanging out, and his close friend texted him and wanted too hangout, well my boyfriend told his friend that he was with me, and then his friend called him "whipped." so im thinking that his friend is jealous of him hanging out with me, me and his friend don't know eachother at all on a personal level, so there isnt any reason that he should be jealous over me.My boyfriend and his friend hungout on Monday & Tuesday, then Tuesday night he came over my house, and not 3 hours since he's seen his friend, his friend is already texting him about coming over Wednesday. The only reason im concerned is because i believe he is competing with me. my boyfriend COMPLETELY disagrees & wont look at it from my point of view. We have also argued about this alot, i have came too the point were i want too make him chose between his friend or me. but its not gonna work. Everytime my boyfriends not with me, hes with his friend. & everytime his friend doesnt want too hangout, he comes too me, as if im his second choice? im really confused & i dont know what too do, im too the point were i cant talk too my boyfriend about it at all because he takes his friends side. how can i explain it too him? or am i doing something wrong? please help. - sasha.