Yes, the way I imagined it there was an explicit agreement that they are free to do what they want discreetly, but if either of them wants to date someone they'll go ahead and divorce. They're living under the same (very large) roof, but basically live their own lives.

I imagine that John was suppressing so much of what he wants and who he is, that there was no longer an actual husband for his wife to live with and at some point she just gave up because there was no getting through to him.