Hey there,
i am a female, and dude, your problem sounds a bit painful! I would suggest going to your doctor (or a doctor you feel comfortable taking off your pants with) and discuss your problem. Since the skin itself is cracking open, the last thing you want is bacteria to get into the cracks and create further problems. I do not know of any std that sounds like what you have, but I am not a doctor. Maybe this could be a skin irritation or something (like because of soap or detergent). I would go to the doctor if I were you, just to have things checked out.