I was chatting with a friend tonight about some difficulties she was having with one of her friends. To summarize, she felt that the relationship was being somewhat trivialized by actions of the friend, and that made her feel shitty. I'm sure that we've all been there.
I've struggled with this situation countless times. Friends I've had for many years have in some way made me feel like I wasn't worth it, despite some amount of history or commonalities or whatever, and it hurts. The only thing I can really gather from those situations is that it's not a reflection of my value in the world.
The only real coping mechanism is to accept these relationships for what they are. It's easy for me to say that people inevitably disappoint you, but I know the opposite is true as well. People can be truly remarkable. People who mean the world to me have also virtually kicked me in the nuts for one reason or another, and it's hard to see sometimes why I admired them as I once did. All you can really do is accept that stuff happens, and either accept what's there or move on.