Stop beating yourself up. If you did not feel hurt or confused after the dissolution of a relationship, you'd be missing the emotion gene. I know, you thought the world would end before your relationship would. Mutual friends often don't know which side to take. Remember, there are always three sides to every story - yours, mine, and the truth. I, too lost those I thought were friends after a breakup. Yes, some may have gone with him, but I believe many just chose to stay away from both parties, caring for each of us equally, and being just as confused as you are, finding it easier to just break ties with both parties.
Sometimes it helps to diary your feelings; doesn't have to be done daily, just write down what you feel or what you think as it occurs, especially those thoughts that you can contradict yourself. Note what was good, what hurt you, why it hurt you, what you expected and didn't get, or what you didn't expect and did get. Later, a month or perhaps two, go back and reread your notes. Often you'll find the handwriting was on the wall all the time; you didn't see it because you were emotionally involved and wanted it to work so badly. When you love someone you tend to believe only the good stuff.
There is a terrific book "Notes to Myself" by Hugh Prather, first copyrighted in 1970. It is not a story, nor can it be called fiction or non-fiction, but rather a collection of thoughts he jotted down, and in doing so was able to go through a sort of self-analysis. This was the first in a series he wrote. Powerful stuff! Good luck to you from someone who's been there. By the way, if anyone tells you they've never been there, they are lying!