Flat rear tire on Hybrid e bike

I have had repeated problems with back tire going flat. Be sure you check out how VERY COMPLICATED it is to get that tire and tube out for repair. It took my mechanic husband two days to fix and the tire went flat again in about 15 minutes. We put in a cushion around the tire to protect from spokes but guess we need to put in several. Also, good luck finding a tube for this size tire.