What does "Paramour in waiting" mean?

I'm reading a romantic story, all written in letters to each other. I'm now at the part where the female writes "Hello my paramour in waiting"; I looked up the word paramour and one definition is "the lover of a married person".

Since this is in the beginning of the story, and the characters background hasn't been fully unveiled, what might I infer about her / him?

Solution 1:

Apparently, a paramour-in-waiting would be one who hopes to someday be the paramour of a certain someone. An aspiring paramour, so to speak.

"In 1951, (Nina Foch) played the ritzy patron and paramour-in-waiting opposite Gene Kelly in the musical 'An American in Paris'..."

As much as the idea is uncommon, so seems to be the phrase itself in literature. It sounds more like these days the boy asks 'I love you, do you love me?' and the answer is 'Get yourself a job and then I will love you.' She waits for him to get a job so she could start loving him? :\

Solution 2:

Paramour used to mean simply lover or wooer, but has tended to become associated with an illicit lover (perhaps because a relationship by marriage was often for social or economic position, whereas a relationship outside of marriage would be for love, par amour).

Little can be inferred without more information, but one can say that the female knows that her correspondent wants to be her lover (and is not yet her lover), and he is willing to wait until circumstances or attitudes allow that. That the paramour in waiting phrase is parallel in form to lady-in-waiting suggests that she might be implying his position may be socially inferior but that it is an honor to be a potential paramour.