Human nature does not change, ever.
Plato’s “the allegory of the cave” and the “matrix” are the examples
Even if you are Christian it does not change. The Apostle Paul talked about the two natures (flesh and spirit), and he fought the battle to the end of his days. Maybe the harder a Christian tries, the more the temptation has become. We have seen this in many pastors that were of excellent character, until they weren’t. It has nothing to do what Christians call ‘salvation’, but everything to do with our own natures.