Husband is disapproves of my attitude towards cleaning

Here's the situation. I'm a housewife with no children. We're (just him and me) renting out a large house (5/6 rooms, two kitchens, two toilets, two levels) from his parents (out of financial obligation), paying more rent than we otherwise would.

I, of course, as a housewife, am happy to be responsible for the household chores.

However, I deal with the situation by basically pretending downstairs doesn't exist. We don't ever use downstairs. I close the door (it's basically like another house with its own kitchen), and I very rarely clean it. Maybe once in a few months.

My husband says he feels resentful, especially when he sees me watching TV or 'wasting time'. He wants me cleaning it at least every couple of weeks, even though we don't use it, he feels I should feel responsible for a house I'm living in, since I have the time.

I would really like your opinions on this, and of I'm being unreasonable in this situation.