I think you need to tell us what you're wearing. If you're wearing the padded pants that 'real cyclists' seem to deem necessary (because the industry only makes saddles that require them), I have no sympathy for you. If you've got a sensible saddle, such as a Brooks, and wearing normal clothes, maybe we can help.

Personally, I've used the same pair of running shorts for the last eight years and they're still going strong. I might even wash them this year.