A couple in need of refreshing or rethinking a marriage in the comparatively restricted era a century ago when divorce was possible but socially not easy to live with, would likely take time away to think it over. If they of reasonable means it could mean going around the world on a pleasure cruise separately, and of course an earlier generation might simply have arranged separate bedrooms or - if they were higher or lower than middle class - have separate intimate lives with others outside the marriage a la French (upper class? not necessarily), too. But this era, beginning of open thinking and lives, and a bit more honesty, would prompt them to more honest solutions towards saving the marriage honestly or do whatever it is honestly.
Now if George Bernard Shaw is going to consider this question he naturally comes up with two couples that have gone their separate ways around the world and have not only come across one half of the other each but fallen in love, and to throw in more fun they have very different attitudes. One falls in love desperately but is shocked at the beloved wife of another takes it as not so difficult or immoral as long as they don't do anything physical, and another has exactly the opposite position.
Of course, post our first encounter with the first pair of lovers in quandary of what if whether, soon the two couples meet, the men discuss, and it is all funny if more intellectually when reading, but competent performers (one can imagine David Niven, Cary Grant, and women to match) might make audience roll in aisles with pain due to laughter too.
Of course, real life couples do not have so neat or happy solutions, there is far more pain and mess, but all the more reason to look to literature and its more visual experiences of theatre and film and now television for some relief, some smiles, laughter, and forgetting of pains. In this as ever Shaw succeeds albeit with a bit more intellectual level than say Jeeves, or perhaps one might compare them on par, but this one certainly could serve the purpose.
