Why do you feel you need to pay for his entertainment? There's no reason you have to fund him 100%. He's a big boy; let him earn some money. My son and daughter both babysat, mowed lawns, etc. We've always been very generous with the pocket money but when we started feeling like you're feeling--abused, is it??--that's when we said to our kids "You want to eat out/go to the movies/whatever, you pay for it yourself." It's amazing how little they need to entertain themselves when THEY'RE the ones who are buying.
If this sounds a little too radical for you, I'd suggest going halfsies. Call it "matching funds" if you'd like, but it requires kids to put a little of their own $$ into the pot. Again, it's amazing how they pare down the partying when mama and daddy aren't doling cash out every time they request it.
BTW, you're very lucky to have SoWal. I learned all this the hard way, as our now 19 year old son nearly bankrupted us without our even noticing. A dollah here, a dollah there....