penile fungus

My boyfriend was recently put on ketoconazole for an infection he has on his penis. He told me he masturbated for too long and now is on this medication. I don't know if he has an STD because he is not being completely honest with me. I don't know if fungus on the penis is only sexually transmitted. I am STD free, or at least was when we first started dating. Now I am scared that he has something and don't know whether or not he has cheated on me or just has a fungal infection. Please help me clarify.

[auntiejessi]

If he is using ketoconazole, its for a fungal infection.  Think jock itch, yeast.  Both are usually not the result of sex, and if this is the only reason to suspect he's cheated, I'd say it occurred naturally, just as it does when you get yeast.

Aj