I’m with @Shoeless. In every stanza the singer tells the sing-ee it’s a lie. And Buddy Holly/Linda Rondstadt explicitly add "When Cupid shot his bow/ He shot it at your heart So if we ever part Then I’ll leave you (Emphasis mine)
Now it may be the singer is in a state of denial and his love has already walked out, but that’s more subtext than we really expect from Buddy Holly.
One other thing to add: “That’ll be the day” in the Buddy Holly song is a reference to a phrase John Wayne uses in “The Searchers”. And IIRC John Wayne’s usage of “That’ll be the day” was the same: that will never happen. Or as the kids today would say, “As if!”
Yeah–I totally get that, and the Cupid line is also good evidence for “ain’t gonna happen.” But then he goes into “that’ll be the day when I die,” which doesn’t sound like “…of natural causes” to me.
Honestly I find it very confusing. Mixed messages, Buddy!
I think he means “You won’t leave me until I’m dead.” And it’s funny, I always heard it as “That’ll be the day that I die”, not “when I die”, but it looks like I’ve been wrong about that. But I think the interpretation fits either way.
“That’ll be the day when I die” can be interpreted both ways, but it seems to me that “you say you’re gonna leave, you know it’s a lie” has only one interpretation. Therefore I vote for “never going to happen.”
If anything Buddy is gloating about the fact that he has an almost abusive hold over his partner. She says she’s going to leave but “that’ll be the day.” He takes all her love and her money. She’s so much under his spell that only he could ever leave her. What a creep.
I don’t think there’s a lot of point in overthinking it?
He wrote it in a era when Tin Pan Alley used rhymes like ‘moon’ and ‘june’… perhaps he just wanted to knock out a quick lyric for a song he had ready to record?
Buddy’s girlfriend is giving him crap about breaking up with him, so he responds by saying that if anyone leaves, it’ll be him, and he’ll die before shedding a tear over her.
Not a healthy-sounding relationship but not creepy. And not remotely as objectionable as Mick Jagger’s sneering in “Under My Thumb” or Pete Townshend’s “sorry, baby” in “A Legal Matter”.
The Beatles - a well known cover band till about 1964 - had “Run for your life” but John took that one back. Jagger is always going to have “Under My Thumb” if only because that song rocks.