Lyric discussion by psfresh 

First, it's not about a vampire and there's no actual marriage.

Most of this song is pretty straightforward - Townes is describing a life of putting off responsibility, living recklessly for the carnal pleasures, and relying on unhealthy habits to make himself feel more sharp, more in command, more full of fire. In this song the 'night' is analogous to the pleasures he derived from that life style, and the 'day' represents the consequences.

For a period of time this life style was cyclical: 'every cruel day had it's nightfall', 'the turnin' of night into day, and the turnin' of day into cursin',' but it turns out to be ultimately unsustainable. The confidence he had about his exploits is eventually shattered and he sees it for the destructive illusion it was.

The final verse is where it gets interesting, he is describing Tom Waits calls the Magic Bullets (Crossroads on The Black Rider). With any addictive stimulant the user feels more powerful/creative/in charge/whatever while using the drug. It's his 'magic bullet' that allows him to hit the target every time. The more he uses the magic bullets however, the worse he feels when not using, until every day is a bad day and it's the magics or nothing. Eventually the magic bullets stop working and the user is left with nothing: 'He trembles he's bent and he's broken.'

In the end the things that once protected him and gave him pleasure turn on him and become sources of pain. It is in fact his proud and boastful laughter that is the harbinger of his fall. The day and all the terrifying consequences that brings is fused to the night which once was his only balm, leaving him unforgiven and with out refuge.

@psfresh Wonderful! I got that that was the general meaning of the song, but hadn't thought about how it was his own laughter (proud and boastful, as you say) that clues him in.

An error occured.