I would never have another woman - non relative - in the house when my wife is out.
This is how I acted and then I was the one that got cheated on...why is it now that when I think of acting like this it makes me want to barf.
I say, let him bring her over. If he screws her, its on his conscious. If it were the other way around, it would be acceptable and you would be called a jealous, controlling husband by pretty much everyone here. The overwelming advice would be to "give her space"...
So give HIM space.