Hi, my husband gets very ill after performing oral sex on me. He develops diarrhea, bloating,gas and stomach cramps. This occurs anywhere from 24 to 48 hours after. We have been together for 5 years and i have had several STD tests that have all come back negative. We have not had oral sex in over 6 months and he has been fine. However, we recently engaged, and sure enough he develops these problems again. What could this be?