He realizes that he got his heart broken by his ex-girlfriend, and that's why he's now breaking other girls hearts. Then in El Scorcho, that is what I find to be his drunken brawl with himself, where he wonders what he's done, and he's rip-roaring drunk, then he's trying to pick up on women(I asked you to go to the greenday concert...)
Finally, he repents for having broken hearts, and a few songs later, the final apology to his girlfriend comes, (I'm sorry, I'm sorry, I'm so-ooo-rry). So, I hope this gives new insight.