if you have apple devices, you can now share audio on two bluetooth pairs headphones. No need for a long wire, though that doesn't take into account battery life of said bluetooth devices.....
Thank you all for the comments.
Sadly we don't run to Apple devices, and only have Android devices. For the record, when on vacation, we listen to radio recordings of Paul Temple, made by the BBC between 1954 and 1968, reflecting a more gentle era of nightclubs, each with their own big band, parking in the centre of London without issues, houses in Eaton Square; a manservant who goes dancing with his girlfriend at "The Palais", very senior policemen at Scotland Yard who do whatever Mr. Temple tells them; flying in First Class, with a bar to sit at etc; a lifestyle that the vast majority could only dream about at the time. Much of the acting is "hammy" with some dreadful American accents. The baddies are usually "foreigners" and everyone, except the odd mechanic or hat check girl, have terribly posh English accents. Great fun! They are occasionally broadcast by the BBC on Radio 4 Extra.
They are also available online -
https://archive.org/search.php?query=paul+temple
The only episodes we find worth listening to are those starring Peter Coke (pronounced "Cook") as Paul Temple and Marjorie Westbury as his wife, Steve.
All about it:-
https://en.wikipedia.org/wiki/Paul_Temple
Miles off topic. Sorry!