Does the emission of pre-seminal fluid (madhy) require sensing it, and does not sensing it indicate a problem?

Madhī (pre-seminal fluid) is a fluid that usually exits upon arousal, and sometimes arousal occurs without its emission, which is not an issue. The questioner should fear Allah and interact with his fiancée—who is not yet his contracted wife—within the bounds of legitimate Islamic guidelines, because she is still a non-mahram, and it is impermissible to be in seclusion with her or to look at her.