What Does Itchy Vagina With White Discharge Indicate?

I have been with my boyfriend for over 3 years now. We have been having sex for over 2 years and he has been my one and only, same goes for him. lately i have been experiencing a sore and itchy vagina. Right after sexual intercourse there was white chuncky stuff coming out and was on his penis. I am starting to worry and I am not sure if its a yeast infection or not. Please help! thanks much.