Originally Posted by
superpanjy
of course we want to sit together!!

That's not always the case, which is why the question is asked.
The followup question you should answer is: If you increase your chance of getting
one upgrade by splitting the PNRs, and offer to give it to her, will she have good memories of the first class experience even if you sit apart for a while? Will she value the seat room, attention, and food & beverages?