Ummm washing shorts in boiling water sounds like a damn fine way to ruin them. Remember, they're synthetic as in related to plastics. Most chamois have built in anti-bacterial properties, but just like hanging out in a wet suit sitting in our shorts for hours and creating heat and humidity in the area is going to create the perfect circumstances for yeast.
So my favorite yeast infection cure is boric acid. Also good for killing ants! It sounds crazy but my friend who is a homeopathic superwoman recommended it. I go about using it one of two ways. I have empty gel caps I got at an herb shop and I'll fill a few and put them in. The other option that is uber soothing is to buy a vinegar douche and empty it out. I figure the vinegar is the least awful substance to have first been in the bottle. Then I dump a bit of boric acid in the bottom so it's maybe 1/4 deep and fill it with cool water. It dissolves better in hot but we don't want that. Shake the daylights out of it and use!
Usually one round of the boric acid douche will work but in case it doesn't I bust out the gel caps.
Another possibility is that your partner may be giving it back to you once it's gone. Guys can get a yeast infection too! They just usually aren't symptomatic so the back and forth can happen easily.
I second making sure it's not bacterial vaginosis. That can really suck! Worst part is no beer or alcohol during treatment.
"True, but if you throw your panties into the middle of the peloton, someone's likely to get hurt."