Reoccurring yeast infection

So basically about 2 months ago i had a yeast infection and they treated it with one medicine and it didn't go away but the second one made it go away. Now again, starting about 3 weeks ago I have another yeast infection that is being treated now. I do have unprotected sex, but boyfriend does not have any symptoms. Im just confused as to why it keeps coming back. Any ideas? Anything would help. Thank you :)