I'm not surprised it wasn't in the DT; until recently it was unique in oral tradition to the best of my knowledge. Sam Lee has come across a traveller fragment of it in the past year, which is quite exciting. Roud 23268

It is indeed seemingly a remarkable survival as the only other version is a 17th century broadside in the Pepys Collection (Vol4 p139) The Country Cuckold, or, The Buxome Dames Frollick in a Field of Rie, with her Lusty Gallant. Printed by Brooksby, Deacon, Blare and Back in London.

Here is an excellent example of how the oral tradition pares away the unnecessary dross. The broadside labours the same joke in 10 weary stanzas.