Having Fishy Odour Under The Penis. Not Yeast Infection. Subsides With Antifungal Cream. What Could It Be?

I am a 48 year old man with a circumcised penis . I shower at least once per day and have good hygiene . For about the last six months or so, I notice that the skin on the underside of my shaft, starting under the head and continuing through the area where there is excess skin wrinkled up (when not erect), has a fishy odor to it. Some days its worse than others, especially if its warm weather and I am sweaty. It is worse and intense after I masturbate, although my semen does not smell fishy. I did enough internet research to determine that it might be a yeast infection , although the area is not red. nor are there any bumps or discharge, The skin does feel a little greasy / sticky by mid day and thats when the odor starts. I have used tinactin antifungal cream on it, and when I do, I do not get this problem. I have also tried Eucerin and when I apply this I do not get the problem. I have used the tinactin daily for weeks and weeks. When I stop treatment I get about two days odor free, and then by the third day the odor starts again. I am sexually active with my wife only, and we always use condoms as birth control . I am never inside of her without one. What could this be? Old age settling in? Is there a remnant of whatever glands produce smegma, left over from my circumcision? Please advise, and thanks in advance.