It is completely possible that he has a yeast infection and dosn't realize it - sometimes men are so asymptomatic and that's why females get so confused about why they keep getting it!
also, if he is clear, then you need to think about clearing up the candida inside you, not just your vaginal candida. usually when someone has continuous yeast infections it is a sign that they have a candida issue within their g.i. this can be solved through diet and i know Colloidal Silver helps with candida also.perhaps check the candida post forum on here too.
lastly, your body may have built up a tolerance to that over the counter medication for yeast infections if you have used it often enough and it may not be making an impact on your yeast infections.
good luck! i know how you feel! i just got rid of one i had for 2.5 months - it just wouldn't go away and i wasn;t even having sex or anything!