Good comeback! If the husband's not "getting any" at home, he should look to himself and his wife to find out why, instead of just "getting any" outside the marriage. If serious contemplation and marriage counseling doesn't work, maybe they should get divorced instead of cheating on each other.
Not at all.
I think the logic is that husbands and wives both have obligations to satisfy each other to the best of their ability sexually, and to be monogamous, if they want their spouse to be monogamous. If they're not monogamous or trying to satisfy each other there's something seriously wrong with the marriage anyway.
Similarly, they both have a responsibility to support each other and their children.
A woman whose husband gave her no money would have a good case for what used to be called "non-support". I can't see any moral case for prostitution. Dancing at a topless bar, maybe, but not actual sex for money.