My Own Worst Enemy Lyrics Meaning

Seems pretty straight forward, from the first line "can we forget about the things I said when I was drunk" you can draw a conclusion that it's about a breakup over a fight.

He knows he has driven his girlfriend away but believes he cannot change ("the smoke alarm is going off and theres a cigarette still burning")

He's saying that he knows he has a problem but he doesn't know what to do about it.