Interesting conversation, but perhaps we are forgetting the historical context. These men always had to hide their 'proclivities' and were very used to dealing with mixed emotions and duplicitious actions. In the context, the two men could have been merely making hay while they can. George was worried what the menage a trois would produce but took a risk. It worked out different than he thought and left him a little lonely, something he was used to despite his many 'adventures'.
I do not think the story line was forced or contrived, any more than the mixed conventions of the time were....
However, it still may be a literary ploy to change the relationships among the players and if so, lets see how it plays out.
Besides with Calder aboard, perhaps it was better that George was more circumspect.