Sharka,
I agree with Wisnu: the food in Tulamben is decent. I don't think that you or your SO will go hungry. At least in Tauch Terminal, there is enough choice in the menu to provide a satisfying meal for a week, and in a worst case scenario, I can live on Nasi Goren (Indo fried rice) or Mi Goren (Indo fried noodles) for several days. At least once a week, they have a buffet BBQ, and that's a good take. I'm sure Mimpi has decent food too. I didn't venture out so I don't know what the food is like at other Tulamben places.
As far as diving Nusa Penida, keep in mind that not all of the Nusa Penida dives expose you to constant surge and possible up and down currents. 50 dives experience may not be a lot of dives in relative terms, but it also depends a lot on how comfortable you are in the water.
Also, you could request that the operator NOT take you to dive sites like Crystal Bay, which can be pretty wild, but instead to some of the sites on the more sheltered side, like where the Schoolhouse is. At least when I was there, you drift in a current with little or no surge and there was no up or down currents.......and we still saw Mola-Molas, altho they were beyond 100 ft. Be aware also that Nusa Penida tends to be colder water - lo 70's or worse.