Ever since i started rotting (2015), my friends have one by one stopped contacting me. I know I'm not as fun to be around anymore. I'm more depressed, cynical, and tired. The last one has been responding to my texts less and less. I know he's responding to his gf's texts as soon as he gets them. It's the metaphorical knife in the back.
Reverse for me, I stopped contacting my friends one by one because we no longer had anything in common, when we were all in that "young phase" nobody had a gf, we were all basically "on par" with eachother, but later they started to date, have sex, party, etc. WTF would we talk about, its almost assured they'd talk about sex and relationships all the time and I'd only grow to hate them, so I separated myself from them ironically for the sake of "preserving our friendship" or whatever was left of it. If I had continued to talk and hang with them I would have grown to hate them greatly.
Your friends did you a favor and saved you the trouble of coming to the realization that I did. Birds of a feather don't flock together because they look alike, they flock together because they have similar flying speeds, if you can't keep up with the flock you'll be left behind, I was always a person who observed things and thought things through so I saw this coming, so I quickly flew off from the flock and never came back because no matter what I would never be able to keep up, and I may have ended up resorting to trying to damage the wings of others just so that I don't feel bad.
I don't get why you're speaking of this as a bad thing, why the fuck would you want them to stay in contact with you, so they can remind you everyday how great their lives are and shitty yours is? lol. I only have like one "true friend" left and that's because were both losers that can't get a GF, the moment he "ascends" I'm pretty sure I'm going to stop talking to him too because we'll no longer be on the same wave length, we aren't even on the same "paths" in life so I already know our friendship is going to end at some point (he wants to get married and have children, I don't).