Man, she sure changed her mind fast! Her lyrics say that he (Jim Reeves) broke their date yesterday, and she found this new guy today, and she's already in his arms! Furthermore, she has already judged this new 1-day guy, and has already determined that this new 1-day guy is much more true and faithful (paraphrasing here) than Jim Reeves! (That is a really quick judgment ability!)
Here's Jim's response:
"I Won't Forget You" - Jim Reeves