I definitely agree that it's about an ex, but I don't necessarily think he hates anything about her. It's more like he's trying really hard to convince himself that he hates her to make losing her hurt less. "I guess I'll be honest, I could use you around" is him basically just admitting that no matter how hard he tries to deny it, he just really misses her. "And my friends all say he's just the broke-dick version of me. They're just trying to help me get some sleep, I know he's what you need." Her new boyfriend just plain pisses him off, but above anything else he just wants to want what's best for her, and if the best thing for her is this new guy, then he's willing to put aside what he wants in order for her to be happy. Or at least he wants her to believe he is.
I definitely agree that it's about an ex, but I don't necessarily think he hates anything about her. It's more like he's trying really hard to convince himself that he hates her to make losing her hurt less. "I guess I'll be honest, I could use you around" is him basically just admitting that no matter how hard he tries to deny it, he just really misses her. "And my friends all say he's just the broke-dick version of me. They're just trying to help me get some sleep, I know he's what you need." Her new boyfriend just plain pisses him off, but above anything else he just wants to want what's best for her, and if the best thing for her is this new guy, then he's willing to put aside what he wants in order for her to be happy. Or at least he wants her to believe he is.