This work comes from comments from the reader, though not in the
direction he was expecting to go.
Strong passions seem to be less in view than the fiancée’s age (NIGTC),
so the passion alternative belongs in a note, as does the question
whether the man spoken of is the fiancé or the father of the virgin and
the referent of the "it" that "must be so." I have also made more
explicit the four requirements Paul sets out for the marriage not to
take place. Whether they can be combined as idioms is for the UDB and
the notes. I have followed NIGTC in rendering "keep his own virgin" as
(a variation of) "respect her virginity."
"marks" would work if the primary meaning were "evidence" or
"appearance." I’ve put "appear" because Paul may have been using this
as metonymy for Jewish lifestyle.
1 Cor 7:30 change wording & punctuation to reflect the Greek more accurately since Paul makes a deliberate triplicate which each clause tied together with kai.