One who exploited me to the full and now totally discarding me. Is it justifiable?

He did not know how to draft even a simple letter and was a branch manager of an agency. So with a bit of my English I helped him in all his official letter drafting and were close and used to go to the cinema, especially English movies and I even put him in an animal welfare club as a Life Member. He subsequently joined an international famous club and started meeting all the 'big rich guns' and that's it, sidetracked me and does not bother me. Is such an action from one tolerable?