If you haven't seen a gyno for this, you probably should, just to receive an experts advice and potentially end the guessing game. From my experiences, sometimes what appears to be yeast is actually not yeast. Everyone's personal biology is unique - it is common to have a white starchy-like substance in the folds; this is just dead and shedding skin cells and can be easily removed with daily gentle washing. Normal discharge from your pelvis is clear to milky white. If you are experiencing other discharge, that could be due to internal washing - douching is TERRIBLE for you. Never attempt to wash yourself internally, your pelvis is biologically wired as a self cleaning mechanism. So if you rule all of that out...
Stress could be a culprit here. Hypothetical situation: Coincidentally, you have a yeast infection in the same time range as having sex with your husband. Psychologically and physically, this was a bad experience. The next time you anticipate a sexual encounter, you could be building subconscious anxiety, "oh uh, am i going to get another yeast infection?"
Then, coincidentally again, you do get another yeast infection. Now you feel vindicated, and you connect sex with the infection, even though they still may be unrelated. Stress could be causing your infections, trust me.
Based on your reports of irritation, I would DEFINITELY advice you to stop with the otc medication. Instead, shower daily with gentle thorough external washing, even using summers eve or another feminine wash. After you get out of the shower, dry yourself using a blow dryer set on cold. Don't use heat, and don't use a towel on that area. Make sure you dry thoroughly, because air KILLS the bacterias. Spend as much time as possible exposing the area to air - this is the best treatment.
Ok, that's all I got for you. I assure you i do speak from extensive experience and remember to make an appt with your gyno! Good luck!