Revelation fics are bread and butter here, and many different tales have been told about the times when Clark *should* have told Lois the secret. The challenge, should you choose to accept it, is to make the reveal happen at a completely non-essential time.
When would telling Lois the secret do the least amount of damage to the relationship? When is it unnecessary information? If he blurted it out after Lois asked why he wasn't affected by the pheromones? In Madame X, when he could have told her months before during or after the Lex Luthor debacle, and he just doesn't want to keep playing the games and explaining his absences, even though he could have easily gotten away with it? During Resplendent Man's time on Earth? Whatever makes the least sense for you, regarding timing and purpose... And then make it make sense. Justify his reveal.
Just a thought I had, but could lead to some fun outcomes.