Hi Sandra! The members of my family are big pizza eaters, so we've not personally shared an individual pizza at Via Napoli. (In fact, between two adults and two children, we polished off the half-meter!) However, I could certainly see how two light eaters would be inclined to share an individual pizza.
My understanding is that the official Disney
policy prohibits sharing of meals on the Dining Plan, so technically, the answer as to whether two people could share an individual pizza and pay with only one table-service credit would be no. However, many guests report
that they have been allowed to share meals at various Disney restaurants and pay with only one table-service
credit. If you and your husband don't feel hungry enough to eat a large pizza (two dining plan credits), tell your server and ask if you could share an individual pizza (one dining plan credit) instead. Disney wants its guests to be happy, and the cast members try very hard to be accommodating.
I hope you enjoy Via Napoli! Come visit me again at the Moms Panel if you have more questions!