While I've never met anyone named Jody, it was a common nickname decades past in the US Army for the guy who your girl is cheating with while you're deployed. I'm surprised to see it was considered a female name in the time I would have expected it to be more definitely male, given that context.

Looking it up, it appears that the original name was "Joe" rather than "Jody", so maybe that's the distinction in the early 20th.