"Mi esposo come tomate."
Again, this would be awkward english. If you are going to give examples, the translations into english should be common. You "could" say "my husband eats tomato" singular, but more common would be the plural. I think in the end this will lead to poor and inaccurate translations.
I agree with candaceh. It should either be "tomatoes" or "a tomato." A native English speaker would never say "My husband eats tomato."
I remember from another question that 'tomate' was tomatoes, however, in this question 'tomate' is tomato! Is there some rule that defines which it is?
It should be consistent with earlier lessons - tomate meant tomatoes then, and it should here as well as the sentence is the same I think.
Bad English. My husband is eating a tomato, tomatoes, some tomatoes, tomato soup, would all be OK. You never say just "tomato."