There are two possibilities:
a) Jenny is Jimmy's husband (I can imagine Earth One Jimmy, makes sense with certain other elements in MOS), and he will appear in the sequel, either to fix their relationship, or because she dies and wants to know from Lois about Superman, creating tension.
b) Jenny is Jimmy's mother, and will appear in the sequel as he is following his mom's footsteps, etc. (aka classic Jimmy).
P.S. I'm sorry, but I can't help but see Jenny dying as an idea.