I've had this happen before, and you captured so much of the hurt and heart-brokenness, which I think most people attribute to relationships concerning love, not always friendship. It's also hard to wonder if and why and is there even a reason as to why this person strayed from you, or doesn't care or want to be around you anymore. I think too often, we blame ourselves, or make excuses for them. I've learned that sometimes, people change, or I've changed, and not for the worse necessarily. I found it difficult in high school to realize that friends were leaving simply because I was dealing with my own depression. I didn't understand it, and I'm sure they didn't either. I wasn't the person they knew on the outside anymore, even though it's far more complex than that. And there was distance with another friend of mine that I don't know if we could have salvaged. It was confusing, and it happened in a way where it seemed we just grew apart in an awkward way. Sometimes we can't articulate or get an answer, and you penned that quite well, how painful that can be in wanting closure, in how we move on when we're in that space of not friends, but not enemies either.