Basically like the title says. I'm in my twenties and what I've noticed these last few years is some sort of pattern. This pattern always seems to follow my best friend. Basically on discord I'm in 1 group of friends. These friends all have other groups besides this one group and I do not. 

It sounds silly, but it really makes me feel like crap what I'm about to say now. 
Basically, whenever I meet someone I feel forced to invite this person into the group, which I don't want. It's almost like I don't want to "share" this person with ppl who don't "share" ppl with me. 
The thing that hurts me the most is that these people tend to get closer to my friends of that time than with me, which makes me feel like I've lost a friend and it really just sucks. 

I also don't really know what to do about it and about myself.