How do you deal with the fact that you can't share what you love and care about with other people?

I have a gf but despite being together for many years I still feel like she doesn't get me, same with everyone I talk with. I have no problem talking to people, but it just feels so insincere I no longer enjoy it.

This has made me reach the conclusion I should just further isolate from the world, do you guys ever feel like this?