That is entirely plausible. I'm actually startled by the idea of him implying sexual freedom for his wife in the first place, but hey. Anti-Machiavel.

I can totally see him going around saying "Everyone should have freedom to have affairs and do their own sex thing, vive la liberté!" and then when presented with the actual thing from his actual wife... maybe might not feel the same way about it.

You almost literally quoted from Mein Name ist Bach there. In that case (since I don't think you've seen it) it's his unmarried sister having an affair, Fritz throws a fit, and she says, "You're always saying everyone is master of their own fate and arse in this kingdom, but by 'everyone' you mean 'you'." :P

So like I said, that's why I can see him deciding that his wife needs to sleep with someone of his choosing, but not that she's allowed to sleep with someone of her choosing.