The title borrows the language of a country-song betrayal, but Bonta turns it somewhere bigger. The "cheating rogues" aren't unfaithful lovers; they're all of us, because we're "already married to time," and so already committed to something we can't walk away from. The joke is that cheating implies a way out, and here there isn't one.
The second stanza shifts the marriage into a legal image. A "hard heart" is like a contract nobody really read or understood, except the undertaker, the one person who knows how the deal ends. The last lines make him a figure who "would not be content / with fair words," meaning charm and good intentions won't settle the debt.
The speaker sounds wry rather than panicked. The tone is dry, almost joking, but underneath it is a cool awareness of mortality. The mood is darkly amused and quietly unsettling.