I remember when my husband was diagnosed just over 9 years ago now. We threw out all the flour and pasta, which we replaced with gluten free varieties.
We then went through our cupboards, and fridge/freezer checking the ingredients list on everything. For example we gave boxes of Oxo cubes to a neighbour, and replaced those with Knorr.
The only useful advice we got from dietician at our hospital was to have separate toasters, so we have toasters in different colourways. I still eat wholemeal bread, as it's so much cheaper than the gluten free ones. We keep our bread in different drawers in the freezer as well, just to be on the safe side.
When we go to a holiday cottage we take a toaster bag so that we can both use the same toaster, other than that it would mean toasting his bread under the grill.