People change I guess, for many reasons too...They also drift into and out of our spheres and that's ok. I guess we need to be true to ourselves, and they them, so I'm not to fussed. I'm really good at drawing a line beneath a person and moving on without any more thought invested. I've learned to do that over the years and it helps me have a happier life.
As they say in my country, clean slate... move on.
I used to have a harder time doing that when I was a teenager or younger.... no longer
I think people struggle to do it when young as they're seeking acceptance or validation maybe. When we get a little older, and grow into self-acceptance and self-confidence it's easier.
You said it well and so it is. Life makes us learn.