Let go of a friend...
I think of of the hard lessons to learn in life is to let got of relationships. Friendships, etc.
The Ego/Id/lizardbrain teaches us that growth is continuing expansion. Which means of course that if you "lose" a friend, you have failed.
But we all grow and change, and sometimes this means that we no longer fit into each others' lives in the way we were were used to. We find new horizons and new learnings, and that can sometimes mean that we have to let go of older friendships, so they don't hold us back.
This can be painful, sadly.