Well, I recently got a girlfriend  and we really make a good couple, I like her a lot and she likes me a lot too. For about a bit more than a week she added my bestfriend on facebook without laying anything (because I had told her about him) and they started talking, and then they both told me they really got along, I felt it pretty weird but I said it was cool. Anyway, now and then they both keep laying things about the other and I keep finding it really really weird, something like, if I don't have my space. I don't have many friends (and I like it that way), he's basically the only person I talk too and, I really don't know if it is okay that I feel this way, I would tell them what I feel but I'll feel pretty selfish then.  


 On one side, they both are free to do what they want, and also like two months ago his ex (they're still friends) added me and he told me he found it weird but he didn't care that much, his ex and I talked by message, but about irrelevant stuff and no more than five times (now she hates me and we don't know why, don't care though). And on the other side, she's like slowly interfiering in my group of friends and adds everyone she know's is my friend, somewhy, and it bugs me; again, I don't know if it's okay for me to feel that way. And really stupid yet real and strong insecurities pop up now and then, so I know there's shit I gotta get together. What do you think?  


TL;DR: My (new) gf and my bestfriend are becoming really good friends, it bugs me a lot and I don't know if it's wrong, I feel selfish, AITA?  


Ps. Let me know if I lack on details