Boys With Girlfriends

This song is not even close to immature, unless you yourself have had nothing but immature relationships. She is not purposely trying to steal the guy's girlfriend like some vindictive 16-year-old cheerleader. She fell in love with her friend, who happens to have a girlfriend. It's not a conscious thing. You don't say "hey, this guy is pretty cool, but he has a girlfriend... oh well, I'll go after him anyway". You wake up at night because you can't sleep. He likes you too, and can't help flirting a little bit, and those brief moments when he smiles become all that keeps you going. You stay up all night talking to him because he's just that easy to talk to, and his girlfriend starts to grow suspicious of the time you spend together. You don't want to break them up. If you had one wish it would be to fall out of love with him, but whatever God you pray to ignores your pleas. But pretending he doesn't exist it only makes it worse. Whether you actually do anything with him or not, your tortuously tight friendship starts to put a strain on his relationship with his girlfriend. Eventually he'll "play the victim", saying he always meant it to be purely friendship (which of course both of you do, but can't help the flirting and such). In this situation you always look like the horrible homewrecker, and he the poor victim who fell prey to your "seduction". You'll get what's yours (reputation, ostracization, etc) eventually, and you know that, but there's nothing you can do once you start the process.

And that's how you learn not to be friends with boys who have girlfriends.