I went through basically the same thing with my boyfriend. He was using jock-itch cream, powder, gold-bond powder...You name it.
Finally, he showed me and I told him it was a yeast infection. He doesn't work out in the heat, but he was on antibiotics for 2 straight months treating bronchitis. I know I always get a yeast infection every time I take antibiotics, so I rarely ever do take them.
We went to the store and I showed him what we needed to get and of course, he had a real problem with it...Treating his problem with a women's medicine...
Then I fussed with him right in the store, embarrassed him a bit probably, but to shut me up, we got some.
He started using it, and in less than a week, his problem was gone. He listens to me much better now!! Lol!
Yeast flourishes in warm, damp places.
I hope it helps.
Libby