I wanted to make a post about this a month ago and ultimately decided it just wasn't worth it.
About two months ago she stopped talking to me or asking to hang out, and the rest of our group of friends stopped inviting us to do anything. Adam said something to her boyfriend and was told that nothing's wrong. I said something to her and her reaction was not one of surprise or sadness that I was feeling left out. She practically yelled at me. Things aren't better. They invited us over and it was just awkward. No one talked to us. (Yet nothing was wrong, apparently.) We were a group of three couples. Earlier in the year, the boyfriend of the other couple was constantly ****-talking the youngest couple and not inviting them anywhere, so I'd text them and invite them myself. I imagine he's doing the same thing to us now, but neither member of the younger couple cares enough to invite us, I guess. It's not worth it anymore. She asked me to hang out a couple weeks ago, but I think it was only because I had gotten her a present for her birthday. She acted like she had no interest in being there, and the next day they all went out to dinner together without saying anything to us.
Sorry for what turned into my own vent, but I understand how you feel. The hardest part is not understanding what went wrong, but I don't think I'll ever get an answer. Just need to move on and find people who actually care.