Yeast infections are uncommon in men. They show themselves as intense redness with pustules around the edges, which is not what you're describing. Most likely you just have friction from a lot of sex. Lubrication and perhaps some rest periods should be sufficient. If symptoms persist, you might show a doctor. (Women who have yeast infections have itchy or sore vaginal discharges, by the way.)
Best.
Dr. Rockoff