Yeast Infection Cause??

So i'm terrified of getting another yeast infection. i've never had one before my last one so i was caught off guard and im trying to avoid it at all costs. I'm not sure what could have caused it. i believe it could have been because my bf gave me oral sex while he was sick. now i'm scared to use all my favorite soaps (never in my vagina just in general) even tho nothing like this happened while i used them as a virgin. could that be the cause or is my body reacting to things differently now that i'm sexually active?