I picked this quote because I believe that Finny felt like this when he returned to Devon. When he found out Gene was going to leave him to go to war, Finny felt hurt. He felt he wasn't as important to Gene as he thought he was.
Beware of the term "best friend" or "soul mate" these are terms a lot of narcissists use to draw you back in, keep you hanging on and to further abuse you without responsibility. Don't you cheat on all your best friends?
Friendship is not about people who act true to your face. It's about people who remain true behind your back. Very True! and it's about people who act true to your face too, under different circumstances.