Green’s Dictionary of Slang

a married woman who frequents singles’ bars looking for brief encounters.

[1962		P. Klee ‘Individuality’ in Some Poems by Paul Klee 15: Aunt Chatterbox gossiping in a corner. / Chambermaid Lewdie, giggling].
1979		J.Homer Jargon 210: Lewdie is singles-bar talk for a married woman looking for a one-night stand.