Well, this is a sad week. I've broken 3 E strings so far, at 10 gauge. And even when I'm not playing them. When I'm jamming on the low E string, the high E has broken. When I'm playing on the B string, the high E has broken.

Why am I breaking so many E strings, but no other strings, even when I'm not playing it?

I write songs.
Currently Requiring Crits:
Your neck might be unleveled causing stress on the strings when another string it plucked, find your truss rod(located on the head of guitar) and loosen it up. That should help, if not send me a message.

Guitar: Oscar Schmidt Acoustic

Piano: Yamaha EA

Microphone: CAD U37
before doing anything with the truss rod, you should check both the bridge and the nut to see if there are any jagged bits that could damage the string causing high stress points.
In addition to the advice above, check the saddle pieces and nut for sharp edges.

edit: Curse you, MapoftheHead, beaten by seconds.