Q: Wheel bearings fail & new part can not be found

On the passenger side, the wheel bearings keep going out. Already, I have replaced them four times on the passenger side, plus replaced the driver’s side wheel bearings and now have no problem on the driver’s side. I was thinking it might be a bad spindle, but I can not find a new spindle anywhere. My van is a cargo van rwd. The parts that I found are for an awd and 4x4, which is not what I need. For more details, I greased the bearing and made certain that it got in the cracks. The only thing left that I can think of is the spindle. One time while driving 70 mph, it went out and I pulled off the nearest exit and the whole tire literally fell off. All that was left on the spindle were a nut, washer, and car key. I can hunt for a whole piece at a parts place, but I prefer to find a new one. Can you tell me where I can find a new one?