Ines I do not currently hold keys for a "virgin" girl. I did once, but it was a little complicated, because she was not able to express her desires, states of emotion and goals very well. I am not saying this was because of her virginity, but maybe because of inexperience.
Relationship? Well chastity seems to be contagious, so if a girl joins her friend in that, and she communicates well, I may hold keys for both of course. Or were you asking if some lady was in a relationship? There was a relationship once, but I think an external keyholder should pull out as soon as their relationship gets serious.
Motivation is the magic in chastity. I am still a fascinated observer, and as curious as you. I do not think your motivation is "very usual", by the way.