Lyric discussion by xdvr 

Cover art for We Came Along This Road lyrics by Nick Cave and the Bad Seeds

I always thought he was referring to himself: "My wifes lover" = him. "smoking gun" = temper

"There never was no other I was your friend Till we came along this road"

I think "momma" is a 70s referral to her.

"Guns blazing at his hip" = full blown argument, when you just shoot to kill. Heavy words are very lightly thrown with force during arguments.

It's just a breakup song, disguised a bit as being about murder. The only thing murdered was their relationship on all layers.

I actually believe it IS about a murder, since that's a recurrent subject on Nick Cave's discography. In fact, I do believe the gun exists and it is, as the main character says, his wife's lover gun.

I imagine he surprised both of them in the bed and, after a fight, he ended with the gun in his hand and shot them. Aftewards he wanders without a plan, with is head spinning, feeling all the bitter emotions of such an act.