Learned to perfection
Society sometimes helps model people into quite interesting and unique individuals with somewhat common traits. I have observed this in people with fantasies, maybe dreams or daring ambitions.
The secretiveness that governs the quest should be a case for study; it might well have been studied, who knows?
They come across as knowledgeable of what they want having relived the fantasy so many times, it has become experiential as to be performed as rote.
First time every time
Having satisfied that fantasy, the truth then emanates that it is really just the first time and then a torrent of denials follow.
First about whom they are and how their deviation of the public façade they present is an anomaly, then about their fears about being discovered calls for utter discretion.
This is quite duplicitous and probably dishonest too, the secret double-lives puts all interactions at varying levels of risk as the protagonist finds an accommodation that balances quest and guilt with managed daring and pangs of conscience.
The art of denial
Using the device of denial, they deign to wipe the slate clean every time that each real repetition of the fantasy is projected as a novice who just seems to have the deft hand of the expert. Denial has become an art form, practiced with all the necessary safeguards to prevent the Jekyll and Hyde lives in the same person from visiting each other.
At which point you begin to wonder, who you can believe and who has created a world of make-belief, therein lies the erosion in trust of strangers with fantasies.