I think I am going to us cast iron to bake pizza, I have broke many stones usually just when I think this one is going to last for ever! Most break when I use my sauce, the water boils on to stone and it cracks.
Regarding your pizza stone cracking, it isn't clear exactly what you're doing in terms of placing your pizza dough on the stone and water causing your stone to crack, etc. Your pizza should have the sauce and toppings on top of the dough before you place it in the oven on the stone. You can use a peel lightly dusted with semolina flour, to avoid having the pizza stick to the peel. Then slide the pizza off the peel onto the stone and cook for the time specified by your recipe. When placing the sauce on the pizza don't place too much sauce on the dough, distribute just enough sauce to lightly cover the dough. Also leave at least a 1/2 inch clean lip around the outer edge of the dough and either spray or brush the lip with olive oil so that you get a good crisp outer crust.
OR you can bake your pizza in a pan until the crust sets and it begin to brown and bubble, then, using a spatula, loosen it from the pan and slide it out of the pan onto the stone for the final 5 minutes of baking. Depending on the temperature of your oven, and thus your stone, after about 3-5 minutes use your spatula or peel to lift the edge of the pizza to check bottom to make sure the bottom isn't burning. The stone will get very hot during the preheating process so be careful how long you leave the pizza on the stone. Incidentally, you should preheat your oven with your stone in the oven at least 30 minutes prior to baking. Typically, the oven needs to be hot when baking pizze (450-500 deg. F.).
My last stone cracked. Thats because I baked bread on it and was flicking water onto the bread and oven walls and the water/moisture landed on the pizza stone and it cracked the whole way through.
I have no suggestions. except maybe using a thicker sauce or using less of it.
SOrry, but I know how much of a bummer it can be!