This is the trouble with cheating: there are no acceptable rules, or laws. It could be a smile, or dancing to a song that you considered to be indefinably 'ours'. It can feel like cheating to go to a restaurant that you used to go to with someone else. Keeping photographs of exes can infuriate, like retrospective cheating.
If you're bored, it's because someone else is fulfilling his dream. Become a bore. It's the most interesting thing you'll ever do.
I have never been able to read Agatha Christie - the pleasure is purely in the puzzle, and the reader is toyed with by someone who didn't decide herself who the killer was until the end of the writing.
Reading a newspaper is like reading someone's letters, as opposed to a biography or a history. The writer really does not know what will happen. A novelist needs to feel what that is like.
When you're working with someone new, it takes a second to understand their instincts and range. It's not really conscious.
Make your work deeper and better than those before you, and eventually someone will notice. If you don't think the work is better than what you've seen, then go back until it is.