Jealousy or something else?

The following post doesn't necessarily relate to the gay community, however since all parties involved are gay I felt it best to post it here. So, i have a boyfriend who has a best friend. I, of course, also have a best friend. Naturally every party involved has met and formed a relationship to an extent. However, i see that the relationship between my best friend and boyfriend's best friend has gone a bit too far. It has gotten to the point where my best friend goes out of his way to meet up and hang with my boyfriend's best friend alone. The relationship is not at all romantic or leading to that. Trust me. Normally this wouldn't bug anyone. Why obstruct a good relationship from occurring, right? But when my best friend has also gone out of his way to meet up with even more of my boyfriend's friends that he barely knows, red flags start to pop up. I would have liked a relationship with my best friend in where no bias towards my boyfriend or his friends would be used against me, but now I'm thinking that those lines have been crossed. Mind you my bff and my boyfriend's bff also "play" makeout and shove it in both of our faces. I have told my friend how i feel about this situation, yet it has consistently continued basically ignoring what I have said. I can also definitely see that the relationship between my boyfriend and his best friend has, in a way, declined a bit. This wasnt so until my bestfriend decided to build a closer relationship with him. Am i being immature or jealous about the situation or am I right in my feelings?!