Hi! I liked your article.
Disappointment really is a concern, even if we know where they came from sometimes we get caught by it. :)
Is hard to remove it because we have fears and desires.
But is possible to overcame, by doing what you said, by accepting the other the way he/she is and also the way you are as the fundamental. Accept the live as it is. It also requires to understand life, how people behave, how there different life experiences turn them to respond differently.
Don't assume the you give/show love is the right one, or the only one way.
You must trust yourself, find someone that also trust themselves, and then trust in each other. Don't thing to much and try to feel more, some feeling are the mind triggers it may have nothing to do with reality.
The only true feeling is the one your mind don't enter, or start it.
So if you feel the others love, them there is nothing needed to prof. There is no right behavior, so there is no behavior to expect.
Cheers!