Hello,
a yeast infection can be caused by a number of things, if your undies are too tight, it your are wet down there alot the mositure can cause it, if you are allergic to the laxtex of a condom, or the soaps that you use scented. But I agree with ^^ if you are getting them back to back after being treated, it can be caused by your sexual partner, doesnt mean hes cheating, maybe hes not showering right away, and bacteria is getting there. Your right a yeast infection can easily be treated, but if left untreat it can turn into more! I would suggest to go see a dr, they will give you a cream or a diflucan pill. I would explain to your boyfriend that its very important to shower after sex, and that s yeast infection can be caused by a number of things, show him online, so that hes not all freaking out, becaue men dont understand our women problems we have to physically show them. So thats what I would suggest, and just tell him that its nothing bad, that you all just have to work on it together! Good luck, adn let us how it goes.
Hugs.
Babydance143