First "breakup"

You know what you do?

If her parents like you:
You go to her house, when she's not home, bring an empty box. Ask her parents if you can put it on her bed for when she gets home. Then, then you jerk off on her pillows and leave.

If they don't like you:
Pour bleach on their front yard at night spelling out some random insult that somebody else called her. They'll never think it's you. =D

Either way man, if you don't want the shit... burn it... The guitar, keep it, keep practicing, get a better one.
Get a gig at an outdoor venue. Make sure she's there. Make sure you play awesomely though. Beforehand drill holes into your guitar and fill them with gasoline soaked rag bits.

At the end of the set, pour some gas on it, light it on fire, and smash it.
Works best if it's done on concrete/pavement stage unless the venue has a wooden stage. If so, you purposely throw it at her, but make it look like an accident.

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