It sounds like you are really hard on your clutch. In regards to the 2nd clutch, perhaps your pressure plate is a bit weak and needs replacing.

The last clutch I broke was in my very first car. I was dumping the clutch to do burnouts when it finally stopped working. When I took it all apart, springs were loose, pressure plate bent and I finally understood what the abuse was doing to the parts.

I have a couple of race cars which I have been racing for several years or more and they both have the same stock type clutch and pressure plates in them.

71 ITB Capri - clutch assembly is on it's 3rd motor combination. Stock LUK Clutch and Borg Warner pressure plate must have more than 60 races on it.

83 GTI Cup car - stock clutch assembly and I've been racing it for several years. Motor is still strong and hasn't been rebuilt yet. This clutch must have about 40 races on it.

I'm careful when I shift, I match engine rpms to rolling speed when downshifting and I when accelerating, I'm make sure my foot is fully out of the clutch before I floor the gas pedal.