My situation is frustrating and I need answers please

I am a 21 yr old male Slim body. Workout 5 times a week. Married and very sexually active. For the past few months I have had an irritation on my penis mainly the head, which was really red and itchy had dry flaky skin. STD' are not a factor. And the doc said its not a fungus. I went and saw a doctor they thought it could possibly be my wife's pH level due to her birth control, which she no longer takes. its been about two months since then and its still there. I have tried using different creams such as aquaphor and cetaphil. When i used each cream it would get better and stop getting better and the skin will just stay really pink and thin until i have sex then it starts getting worse again. We read online about symptoms of yeast infection so we tried using yogurt to help did not work for me. The yogurt acted pretty much the same as the creams. We have tried switching lubes to an all natural lube. We do not use condoms. It does sting sometimes during sex and since i had sex last night more spots have formed down my shaft. Wife does not have any symptoms i have. Like I said i have seen a Doctor but that did not help. I am hoping someone on here could shed some light on my situation, it would be greatly appreciated.

Thank You
Crawl