Not that I condone any of this, but consider that the cultural disgust of marrying a girl under the age of 18 is a more recent and modern taboo. Back then, in rural United States, it wasn't an issue at all. Heck as a Gen X kid whose parents were from the Silent Generation, my mother married her first husband when she was 16 and he was 22. She never thought it was an issue other than she regretted marrying anyone at the age. But her parents, church, and teachers didn't think it was a problem.
It's hard to believe because most people might say Elvis lived in modern society but he's not. The 20th century was full of changes that we don't really think about.
I toked more of that last night - I'm still alive.